Introgression of two yield qtls in cucumis sativus plants

ABSTRACT

The present invention relates to cultivated cucumber plants comprising a yield QTL on chromosome 2 and/or a yield QTL on chromosome 6 of their genome, and to methods for generating such plants, and their use.

The present invention relates to the field of cucumber breeding.Provided is an introgression of a Quantitative Trait Locus (QTL) locatedon chromosome 2 of the cultivated cucumber genome and/or anintrogression of a QTL on chromosome 6 of the cultivated cucumbergenome, which can be used to increase yield in cultivated cucumbers(Cucumis sativus var. sativus), such as pickling cucumbers (e.g.American pickling, European pickling types), slicing cucumbers (e.g.American slicing), long cucumbers, short cucumbers, European greenhousecucumbers, Beit-Alpha type cucumbers, oriental trellis type cucumbers(also marketed as ‘burpless’), Asian cucumbers (which can be furthersubdivided into different types, such as Indian Mottled cucumber,Chinese Long cucumber, Korean cucumber and Japanese cucumber types,whereby the first belongs to the Indian cucumber group and the lastthree are part of the East Asian cucumber group).

The yield increasing QTL on chromosome 2 is referred herein as QTL2.1and the yield increasing QTL on chromosome 6 is referred to as QTL6.1.In one aspect, both are introgressions from the same wild relative ofcucumber, i.e. from the same accession number, and in one aspect evenfrom the same plant. One plant of the accession was used to make adouble haploid population, which was then used to map and to introgressthe QTLs into the European long cucumber type. From this type one orboth QTLs can be easily transferred into any other cucumber type, suchas short cucumber types, or into any other long cucumber breeding lineor variety. Seeds comprising both introgression fragments in homozygousform were deposited under accession number NCIMB 42545.

The yield increasing QTL on chromosome 2 was initially not found, as inthe mapping project a negative yield QTL, reducing fruit weight, wasfound in the same region (see FIG. 1, top is LOD diagram of the positiveyield QTL, QTL2.1, on chromosome 2 and bottom is LOD diagram of thenegative yield QTL, QTL2.2, on chromosome 2).

Only after further backcrossing and yield experiments with test hybridsit became apparent that the positive yield QTL and the negative yieldQTL on chromosome 2 could be separated, i.e. were in different regions.

The effect of the negative yield QTL became apparent when comparing aline comprising an introgression fragment with both QTL2.1 and QTL2.2 toa line comprising only QTL2.1 (and lacking QTL2.2). The average fruitlength was decreased in the first line (comprising QTL2.2) by more than2 cm length.

In one aspect a cultivated cucumber plant comprising an introgressionfragment on chromosomes 2 is provided, comprising QTL2.1, whereby theintrogression fragment significantly increase the fruit yield of thecultivated cucumber comprising the introgression compared to the samecultivated cucumber lacking the introgression. Also one or moremolecular markers (especially Single Nucleotide Polymorphisms or SNPs)which are present on the introgression fragment and which are indicativeof the presence of the introgression fragment and methods of using suchmarkers are provided herein. Likewise seeds, plant parts, cells and/ortissues comprising QTL2.1 on chromosome 2 are provided. In one aspectthe plants, seeds, plant parts, cells and/or tissues comprise theintrogression fragment from a wild relative of cucumber, whereby theintrogression fragment comprising QTL2.1, which QTL is locatedphysically in the region starting at 5.0 Mb and ending at 11.0 Mb ofchromosome 2. In one aspect the other regions of chromosome 2, i.e. from0 Mb to 5.0 Mb and/or from 11.0 Mb to the end of chromosome 2 compriseor consist of cultivated cucumber chromosome regions.

In one aspect the introgression fragment does not comprise the negativeyield QTL on chromosome 2, which reduces average fruit weight per plant.This negative yield QTL is herein referred to as QTL2.2. Thus, theintrogression fragment from the wild relative of cucumber comprises inone aspect QTL2.1, and one or more SNPs linked to QTL2.1, but lacksQTL2.2. In the cultivated Cucumis sativus seeds deposited by theapplicant under accession number NCIMB42545, QTL2.1 and QTL6.1 arepresent in homozygous form, while QTL2.2 is absent (and insteadcultivated cucumber genome is present in that region).

In one aspect QTL2.1 (i.e. the introgression fragment comprising theQTL) is present in heterozygous form in a cultivated cucumber plant,cell or tissue, especially in long cucumber. In another aspect QTL2.1(i.e. the introgression fragment comprising the QTL) is present inhomozygous form in a cultivated cucumber plant, cell or tissue,especially in long cucumber. In a specific aspect the cultivatedcucumber plant is an F1 hybrid, especially an F1 hybrid generated bycrossing two inbred parent lines, whereby at least one of the parentlines comprises the QTL2.1 (i.e. the introgression fragment comprisingthe QTL) in homozygous form. In a specific aspect the cultivatedcucumber plant does not comprise any other introgression fragments onchromosome 2 of the cucumber genome which affect yield, preferablychromosome 2 lacks at least QTL2.2.

The yield increasing QTL on chromosome 6 was found in cold temperaturesand appears to be a cold tolerance QTL, increasing yield in autumn orwinter periods and cooler climate regions. So for example whengreenhouse cucumbers are grown in colder climates or colder periods ofthe year, such as autumn and winter in southern European or Eurasiancountries or cooler regions such as northern Europe and Canada (orNorth-America), QTL6.1 further increases yield of breeding lines andvarieties adapted to that climate. This QTL is, therefore, particularlysuited to increase yield of varieties adapted for colder temperatures.However, it is understood that frost should be prevented.

In one aspect a cultivated cucumber plant comprising an introgressionfragment on chromosomes 6 is provided, comprising QTL6.1, whereby theintrogression fragment significantly increase the fruit yield of thecultivated cucumber comprising the introgression compared to the samecultivated cucumber lacking the introgression. Also one or moremolecular markers (especially Single Nucleotide Polymorphisms or SNPs)which are present on the introgression fragment and which are indicativeof the presence of the introgression fragment and methods of using suchmarkers are provided herein. Likewise seeds, plant parts, cells and/ortissues comprising QTL6.1 on chromosome 6 and comprising otherwise achromosome 6 of cultivated cucumber in their genome are provided. In oneaspect the plants, seeds, plant parts, cells and/or tissues comprise theintrogression fragment from a wild relative of cucumber, whereby theintrogression fragment comprising QTL6.1, which QTL is locatedphysically in the region starting at 25.0 Mb and ending at 29.0 Mb ofchromosome 6. In one aspect the other regions of chromosome 6, i.e. from0 Mb to 25.0 Mb and/or from 29.0 Mb to the end of chromosome 6 compriseor consist of cultivated cucumber chromosome regions.

In one aspect QTL6.1 (i.e. the introgression fragment comprising theQTL) is present in heterozygous form in a cultivated cucumber plant,cell or tissue, preferably in long cucumber. In another aspect QTL6.1(i.e. the introgression fragment comprising the QTL) is present inhomozygous form in a cultivated cucumber plant, cell or tissue,preferably in long cucumber. In a specific aspect the cultivatedcucumber plant is an F1 hybrid, especially an F1 hybrid generated bycrossing two inbred parent lines, whereby at least one of the parentlines comprises the QTL6.1 (i.e. the introgression fragment comprisingthe QTL) in homozygous form. In a specific aspect the cultivatedcucumber plant does not comprise any other introgression fragments onchromosome 6 of the cucumber genome which affect yield.

In one aspect of the invention a cultivated cucumber plant is providedcomprising both QTL2.1 and QTL6.1 of the invention, either both inhomozygous form, e.g. in an inbred parent line, or both in heterozygousform, e.g. in an F1 hybrid generated by crossing an inbred parent linecomprising both QTL2.1 and QTL6.1 in homozygous form with an inbredparent line lacking both QTL2.1 and QTL6.1. As mentioned, in the Cucumissativus seeds deposited by the applicant under accession numberNCIMB42545, QTL2.1 and QTL6.1 are present in homozygous form. However,QTL2.1 and QTL6.1 can also be used independently to generate cucumberplants, breeding lines and varieties with increased yield.

In yet another aspect of the invention a cultivated cucumber plant isprovided comprising both QTL2.1 and QTL6.1 of the invention, whereby oneof the QTLs is in homozygous form and the other QTL is in heterozygousform.

In still another aspect, the cultivated cucumber plant comprises QTL2.1and/or QTL6.1 from a wild relative of cucumber, while apart from theintrogression fragment, the remaining chromosome 2 and/or 6 genome is agenome of cultivated cucumber, in one aspect of European greenhousecucumber.

In one embodiment also the other chromosomes are all cultivated cucumbergenome, e.g. European greenhouse cucumber genome. That is to say that inone aspect of the invention the cultivated cucumber comprises only oneintrogression fragment from a wild relative of cucumber in its genome(comprising either QTL2.1 or QTL6.1 in homozygous or heterozygous form)or comprises only two introgression fragments from a wild relative ofcucumber in its genome, one comprising QTL2.1 and one comprising QTL6.1,while the remaining genome is a genome of cultivated cucumber. In oneaspect, the two introgression fragments are from the same wild relativeof cucumber, e.g. from the same species, preferably from the sameaccession number, optionally even from the same plant of that accessionnumber.

In a different embodiment, the cultivated cucumber plant of theinvention may, in addition to QTL2.1 and/or QTL6.1, comprise one or moreother introgression fragments from wild relatives of cucumber in itsgenome. In one aspect, these other introgression fragments are not onchromosome 2 and/or on chromosome 6.

BACKGROUND

Cultivated cucumber (Cucumis sativus var. sativus L.) is an importantvegetable crop worldwide. It belongs to the family Cucurbitaceae. It isthought to originate from South East Asia from wild ancestors withsmall, bitter fruits, such as Cucumis sativus var. hardwickii.

The cultivated cucumber genome has seven pairs of chromosomes (n=7) anda haploid genome size of about 367 Mb (Megabases) with an estimatedtotal of about 26,682 genes. The cucumber genome was the first vegetablegenome to be sequenced (Huang et al. 2009, Nature Genetics, Volume 41,Number 12, p 1275-1283 andhttp://www.icugi.org/cgi-bin/gb2/gbrowse/cucumber_v2/).

Yield of cultivated cucumber has not increased much over the lastdecades. Shetty and Wehner 2002 (CropSci. 42: 2174-2183) screened theUSDA cucumber germplasm collection for fruit quality and fruit yieldunder field conditions in North Carolina (USA) and suggest that highyielding cultigens identified in their study can be used to develop highyielding cultivars.

WO2009/082222 used on of the accessions identified by Shetty and Wehnerin 2002 (supra), the Turkish Beit-Alpha landrace PI 169383 to identifyQTLs for fruit weight of harvest stage cucumbers on linkage group 3and/or 4 of PI 69383.

Yuan et al. 2008 (Euphytica 164: 473-491) genetically mapped specificfruit traits in a cross between a Northern Chinese Cucumber S94 and aNorthWest European Cucumber S06. Their linkage group 3 appears tocorrespond to the physical chromosome 2 and their linkage group 2appears to correspond to the physical chromosome 6. They mapped a locuscalled fw2.1 (fruit weight) to the top of chromosome 6 (LG2) and theymapped a locus called fw3.1 (fruit weight) to the bottom of chromosome 2(LG3). They mapped a locus called fl3.1 (fruit length) to the samelocation as locus fw3.1, mapped based on the difference in fruit lengthbetween S94 (30 cm long fruits) and S06 (15 cm long fruits). However,they did not map total (cumulative) fruit yield.

Fazio et al. 2003 (Theor Appl Genet 107: 864-874) genetically mapped anumber of traits, including cumulative fruits per plants over threeharvests and morphological traits such as little leaf (‘ll’). Theirlinkage group 1 appears to correspond to the physical chromosome 6. Alocus called fpl1.2 was consistent in both environments and mapped tothe little leaf locus. Little leaf is physically located in the regionspanning 7 Mb and 8.5 Mb of the physical chromosome 6, i.e. it is at thetop of chromosome 6.

Wei et al. 2014 (BMC Genomics 15: 1158, p 1-10) disclose mapping ofimmature and mature fruit length and immature fruit weight in apopulation derived from a cross between a Chinese cucumber inbred line(CC3) and NC76. NC76 was developed from a landrace of Cucumis sativusvar. sativus from Afghanistan (PI246930). They found a QTL for immaturefruit length on Linkage Group 6.

WO2016/059090 and WO2016/059092 both describe two yield enhancing QTLs,one on chromosome 2 in the region of 0.4 to 2.9 Mb of the chromosome andone on chromosome 6 in the region of 26 Mb to the end of the chromosome,introgressed from a single wild cucumber into cultivated cucumber of thepickling type. Seeds of the cultivated pickling type cucumber comprisingboth QTLs in heterozygous form were deposited under NCIMB42262. Thedonor used in WO2016/059090 and WO2016/059092 was a different donor thanthe donor used in the instant invention.

Still, there remains a need for identifying QTLs for enhancing total(cumulative) fruit yield in cucumber to be able to increase fruit yieldof modem cucumber varieties, especially in long cucumber types suitablefor glasshouse cultivation e.g. high wire cultivation or the traditionalumbrella system of cultivation. Especially, introgression fragmentscomprising yield increasing QTLs which do not comprise introgressionregions which decrease average fruit length are needed. Alsointrogression fragments which are suitable for increasing average fruityield in cold growing conditions are desired.

FIGURES

FIG. 1 shows LOD diagrams of the QTL mapping results, where onchromosome 2 a positive yield QTL (QTL2.1, top Figure) and a negativeyield QTL (QTL2.2, bottom Figure) were found very close to each other,with the peak (vertical dashed line) at almost the same position on theX-axis (chromosome 2). The QTL2.2 significantly decreased average fruitlength.

GENERAL DEFINITIONS

The indefinite article “a” or “an” does not exclude the possibility thatmore than one of the element is present, unless the context clearlyrequires that there be one and only one of the elements. The indefinitearticle “a” or “an” thus usually means “at least one”.

As used herein, the term “plant” includes the whole plant or any partsor derivatives thereof, such as plant organs (e.g., harvested ornon-harvested storage organs, tubers, fruits, leaves, seeds, etc.),plant cells, plant protoplasts, plant cell or tissue cultures from whichwhole plants can be regenerated, plant calli, plant cell clumps, andplant cells that are intact in plants, or parts of plants, such asembryos, pollen, ovules, ovaries, fruits (e.g., harvested tissues ororgans, such as harvested cucumber fruits or parts thereof), flowers,leaves, seeds, tubers, bulbs, clonally propagated plants, roots,root-stocks, stems, root tips and the like. Also any developmental stageis included, such as seedlings, immature and mature, etc. When “seeds ofa plant” are referred to, these either refer to seeds from which theplant can be grown or to seeds produced on the plant, afterself-fertilization or cross-fertilization.

“Plant variety” is a group of plants within the same botanical taxon ofthe lowest grade known, which (irrespective of whether the conditionsfor the recognition of plant breeder's rights are fulfilled or not) canbe defined on the basis of the expression of characteristics that resultfrom a certain genotype or a combination of genotypes, can bedistinguished from any other group of plants by the expression of atleast one of those characteristics, and can be regarded as an entity,because it can be multiplied without any change. Therefore, the term“plant variety” cannot be used to denote a group of plants, even if theyare of the same kind, if they are all characterized by the presence ofone or two loci or genes (or phenotypic characteristics due to thesespecific loci or genes), but which can otherwise differ from one anotherenormously as regards the other loci or genes.

“F1, F2, F3, etc.” refers to the consecutive related generationsfollowing a cross between two parent plants or parent lines. The plantsgrown from the seeds produced by crossing two plants or lines is calledthe F1 generation. Selfing the F1 plants results in the F2 generation,etc.

“F1 hybrid” plant (or F1 hybrid seed) is the generation obtained fromcrossing two inbred parent lines. Thus, F1 hybrid seeds are seeds fromwhich F1 hybrid plants grow. F1 hybrids are more vigorous and higheryielding, due to heterosis. Inbred lines are essentially homozygous atmost loci in the genome.

A “plant line” or “breeding line” refers to a plant and its progeny. Asused herein, the term “inbred line” refers to a plant line which hasbeen repeatedly selfed and is nearly homozygous. Thus, an “inbred line”or “parent line” refers to a plant which has undergone severalgenerations (e.g. at least 5, 6, 7 or more) of inbreeding, resulting ina plant line with a high uniformity.

The term “allele(s)” means any of one or more alternative forms of agene at a particular locus, all of which alleles relate to one trait orcharacteristic at a specific locus. In a diploid cell of an organism,alleles of a given gene are located at a specific location, or locus(loci plural) on a chromosome. One allele is present on each chromosomeof the pair of homologous chromosomes. A diploid plant species maycomprise a large number of different alleles at a particular locus.These may be identical alleles of the gene (homozygous) or two differentalleles (heterozygous). Thus, for example reference may herein be madeto a “yield allele” or “positive yield allele” of the yield locus QTL2.1and/or QTL6.1.

The term “gene” means a (genomic) DNA sequence comprising a region(transcribed region), which is transcribed into a messenger RNA molecule(mRNA) in a cell, and an operably linked regulatory region (e.g. apromoter). Different alleles of a gene are thus different alternativesform of the gene, which may be in the form of e.g. differences in one ormore nucleotides of the genomic DNA sequence (e.g. in the promotersequence, the exon sequences, intron sequences, etc.), mRNA and/or aminoacid sequence of the encoded protein.

The term “locus” (loci plural) means a specific place or places or asite on a chromosome where for example a QTL, a gene or genetic markeris found. The yield locus (or yield-increasing locus) is, thus, thelocation in the genome of cucumber, where QTL2.1 or QTL6.1 is found. Incultivated cucumber of the invention the QTLs are found on chromosome 2and/or 6 (using the chromosome assignment of Huang et al. 2009, NatureGenetics, Volume 41, Number 12, p 1275-1283 and world wide web aticugi.org/cgi-bin/gb2/gbrowse/cucumber_v2/) i.e. they are introgressedinto the cultivated cucumber genome (i.e. onto chromosome 2 and/or 6)from a wild relative of cucumber.

A “quantitative trait locus”, or “QTL” is a chromosomal locus thatencodes for one or more alleles that affect the expressivity of acontinuously distributed (quantitative) phenotype. The yield conferringquantitative trait loci (or “yield QTLs”) are named QTL2.1 and QTL6.1herein.

“Cucumber genome” and “physical position on the cucumber genome” and“chromosome 2 and/or 6” refers to the physical genome of cultivatedcucumber, world wide web at icugi.org/cgi-bin/gb2/gbrowse/cucumber_v2/,and the physical chromosomes and the physical position on thechromosomes. So, for example SNP_01 is located at the nucleotide (or‘base’) positioned physically at nucleotide 5,502,468 of chromosome 2,which has a physical size from 0 to 23.17 Mb (i.e. 23,174,625 bases).Likewise SNP_27 is located at nucleotide (or ‘base’) positionedphysically at nucleotide 25,519,964 of chromosome 6, which has aphysical size from 0 to 29.07 Mb (i.e. 29,076,227 bases).

“Physical distance” between loci (e.g. between molecular markers and/orbetween phenotypic markers) on the same chromosome is the actuallyphysical distance expressed in bases or base pairs (bp), kilo bases orkilo base pairs (kb) or megabases or mega base pairs (Mb).

“Genetic distance” between loci (e.g. between molecular markers and/orbetween phenotypic markers) on the same chromosome is measured byfrequency of crossing-over, or recombination frequency (RF) and isindicated in centimorgans (cM). One cM corresponds to a recombinationfrequency of 1%. If no recombinants can be found, the RF is zero and theloci are either extremely close together physically or they areidentical. The further apart two loci are, the higher the RF.

“Introgression fragment” or “introgression segment” or “introgressionregion” refers to a chromosome fragment (or chromosome part or region)which has been introduced into another plant of the same or relatedspecies by crossing or traditional breeding techniques, such asbackcrossing, i.e. the introgressed fragment is the result of breedingmethods referred to by the verb “to introgress” (such as backcrossing).In cucumber, wild or primitive cucumber accessions (e.g. landraces) orwild relatives of cultivated cucumber can be used to introgressfragments of the wild genome into the genome of cultivated cucumber,Cucumis sativus var. sativus L. Such a cultivated cucumber plant thushas a “genome of cultivated Cucumis sativus var. sativus”, but comprisesin the genome a fragment of a wild or primitive cucumber or of a wildrelative of cucumber, e.g. an introgression fragment of a related wildCucumis sativus genome, such as Cucumis sativus var. hardwickii, C.sativus var. sikkimensis Cucumis sativus var. xishuangbannesis, oranother wild cucumber or wild relative of cucumber. So, for example, acultivated cucumber is provided herein comprising a genome of cultivatedcucumber, and in that genome one introgression fragment on chromosome 2and/or 6 of cultivated cucumber which confer enhanced yield compared tothe cultivated cucumber genome lacking the introgression fragments (andhaving a chromosomes 2 and 6 of cultivated cucumber, without theintrogression fragments). It is understood that the term “introgressionfragment” never includes a whole chromosome, but only a part of achromosome. The introgression fragment can be large, e.g. even threequarter or half of a chromosome, but is preferably smaller, such asabout 15 Mb or less, such as about 10 Mb or less, about 9 Mb or less,about 8 Mb or less, about 7 Mb or less, about 6 Mb or less, about 5 Mbor less, about 4 Mb or less, about 3 Mb or less, about 2.5 Mb or 2 Mb orless, about 1 Mb (equals 1,000,000 base pairs) or less, or about 0.5 Mb(equals 500,000 base pairs) or less, such as about 200,000 bp (equals200 kilo base pairs) or less, about 100,000 bp (100 kb) or less, about50,000 bp (50 kb) or less, about 25,000 bp (25 kb) or less.

“Cultivated cucumber” or “domesticated cucumber” refers to plants ofCucumis sativus var. sativus i.e. varieties, breeding lines orcultivars, cultivated by humans and having good agronomiccharacteristics, especially producing edible and marketable fruits ofgood size and quality and uniformity; such plants are not “wildcucumber” or “primitive cucumber” plants, i.e. plants which generallyhave much poorer yields and poorer agronomic characteristics thancultivated plants and are less uniform genetically and in theirphysiological and/or morphological characteristics. “Wild plants” of“wild cucumber” include for example ecotypes, landraces or wildaccessions or wild relatives of a species. Cultivated cucumber plants(lines or varieties) can also be distinguished from wild or primitivecucumber accessions by the significantly lower amount of SNPs (less than2,000,000 SNPs) and INDELs (insertions/deletions of shorter than 5 bp;less than 150,000 INDELs) in the genome and their significantly lowernucleotide diversity (equal to or less than 2.3×10⁻³ π), as described inTable 1 of Qi et al, Nature Genetics December 2013, Vol 45, No. 12,pages 1510-1518. SNP numbers, INDEL numbers and nucleotide diversity canbe determined as described herein, especially in the section ‘OnlineMethods’.

“Indian cucumber group” refers to wild or wild relatives of cucumbersfrom India, having a high amount of SNPs (more than 3,000,000 SNPs) andINDELs (insertions/deletions of shorter than 5 bp; more than 200,000INDELs) in the genome and high nucleotide diversity (more than 3.0×10⁻³π or even more than 4.0×10⁻³ π).

“Eurasian cucumber group” refers to cultivated cucumbers from central orwestern Asia, Europe and the United States, having a low amount of SNPs(less than 2,000,000 SNPs, or less than 1,500,000 SNPs) and INDELs(insertions/deletions of shorter than 5 bp; less than 150,000 INDELs) inthe genome and a low nucleotide diversity (equal to or less than2.3×10⁻³ π, preferably less than 2.0×10⁻³ π).

“East Asian cucumber group” refers to cultivated cucumbers from EastAsia, such as China, Korea and Japan, having a low amount of SNPs (lessthan 2,000,000 SNPs, or less than 1,500,000 SNPs) and INDELs(insertions/deletions of shorter than 5 bp; less than 150,000 INDELs,preferably less than 100,000) in the genome and a low nucleotidediversity (equal to or less than 2.3×10⁻³ π, preferably less than2.0×10⁻³ π or even less than 1.5×10⁻³).

“Xishuangbanna cucumber group” refers to cucumbers from theXishuangbanna region of China, having a low amount of SNPs (less than2,000,000 SNPs, or less than 1,500,000 SNPs or even less than 100,000SNPs) and INDELs (insertions/deletions of shorter than 5 bp; less than150,000 INDELs, preferably less than 100,000) in the genome and a lownucleotide diversity (equal to or less than 2.3×10⁻³ π, preferably lessthan 2.0×10⁻³ π or even less than 1.5×10⁻³).

“Wild cucumber” or “primitive cucumber” refers to C. sativus var.sativus which generally have much poorer yields and poorer agronomiccharacteristics than cultivated plants and are less uniform geneticallyand in their physiological and/or morphological characteristics. Wildplants include for example ecotypes, landraces or wild accessions orwild relatives of a species.

“Wild relatives of cucumber” refer to Cucumis sativus var. hardwickii,C. sativus var. sikkimensis, Cucumis sativus var. xishuangbannesis.

“Landrace(s)” refers to primitive cultivars of Cucumis sativus var.sativus developed in local geographic regions, which often show a highdegree of genetic variation in their genome and exhibit a high degree ofmorphological and/or physiological variation within the landrace (e.g.large variation in fruit size, etc.), i.e. are significantly lessuniform than cultivated cucumber. Landraces are, therefore, hereinincluded in the group “wild cucumber”, which is distinct from“cultivated cucumber”.

“Uniformity” or “uniform” relates to the genetic and phenotypiccharacteristics of a plant line or variety. Inbred lines are geneticallyhighly uniform as they are produced by several generations ofinbreeding. Likewise, and the F1 hybrids which are produced from suchinbred lines are highly uniform in their genotypic and phenotypiccharacteristics and performance.

The term “yield-allele” or “positive yield allele” refers to an allelefound at the yield locus QTL2.1 and/or QTL6.1 introgressed intocultivated cucumber (onto cultivated C. sativus var. sativus chromosome2 or 6 respectively) from a wild relative of cucumber. The term“yield-allele”, thus, also encompasses yield-alleles obtainable fromother Cucumis accessions. When one or two yield-alleles are present atthe locus in the genome (i.e. in heterozygous or homozygous form), theplant line or variety produces a significantly higher fruit yield thanthe control lacking the QTL, preferably the genetic control. Incultivated cucumber plants lacking the introgression fragment, the C.sativus var. sativus allele found at the same locus on chromosome 2 orchromosome 6 is herein referred to as “wild type” allele (wt). As theyield QTLs are dominant, wt/wt plants show a normal yield, whereasQTL2.1/wt plants or QTL6.1/wt plants and QTL2.1 QTL2.1 or QTL6.1 QTL6.1plants are plants which possess the enhanced yield phenotype conferredby the yield-allele(s) compared to wt/wt at the locus on chromosome 2 or6. The genotype of the SNP markers provided herein is also indicative ofthe wild type or of the QTL being in homozygous or heterozygous form.E.g. the genotype of SNP_01 indicative of QTL2.1 is ‘CT’ (QTL2.1/wt) or‘CC’ (QTL2.1 QTL2.1), while the genotype indicative of the wild type is‘TT’ (wt/wt). Similarly, the genotype of SNP_27 indicative of QTL6.1 is‘GA’ (QTL6.1/wt) or ‘GG’(QTL6.1/QTL6.1), while the genotype indicativeof the wild type is ‘AA’.

A genetic element, an introgression fragment, or a gene or alleleconferring a trait (such as yield) is said to be “obtainable from” orcan be “obtained from” or “derivable from” or can be “derived from” or“as present in” or “as found in” a plant or seed or tissue or cell if itcan be transferred from the plant or seed in which it is present intoanother plant or seed in which it is not present (such as a line orvariety) using traditional breeding techniques without resulting in aphenotypic change of the recipient plant apart from the addition of thetrait conferred by the genetic element, locus, introgression fragment,gene or allele. The terms are used interchangeably and the geneticelement, locus, introgression fragment, gene or allele can thus betransferred into any other genetic background lacking the trait. Notonly seeds deposited and comprising the genetic element, locus,introgression fragment, gene or allele can be used, but alsoprogeny/descendants from such seeds which have been selected to retainthe genetic element, locus, introgression fragment, gene or allele, canbe used and are encompassed herein, such as commercial varietiesdeveloped from the deposited seeds or from descendants thereof. Whethera plant (or genomic DNA, cell or tissue of a plant) comprises the samegenetic element, locus, introgression fragment, gene or allele asobtainable from the deposited seeds can be determined by the skilledperson using one or more techniques known in the art, such as phenotypicassays, whole genome sequencing, molecular marker analysis, traitmapping, chromosome painting, allelism tests and the like, orcombinations of techniques.

A “Variant” or “orthologous” sequence or a “variant QTL2.1” or a“variant of QTL6.1” refers to a yield QTL (QTL2.1 or QTL6.1), or anintrogression fragment comprising the QTL, which is derived from adifferent wild relative of cucumber plant than the QTL2.1 and QTL6.1present in NCIMB42545, but which variant comprises one or more of theSNPs linked to QTL2.1 or QTL6.1 and wherein the variant genomic sequencecomprises substantial sequence identity to the SEQ ID NO: comprising theSNP (any one of SEQ ID NO: 1-26 linked to QTL2.1 and SEQ ID NO: 27-40linked to QTL6.1), i.e. at least 85%, 90%, 95%, 98%, 99% sequenceidentity or more. Thus, when reference herein is made to a certain SNPgenotype in a specific genomic sequence (selected from SEQ ID NO: 1 toSEQ ID NO: 26 for QTL2.1 and SEQ ID NO: 27 to SEQ ID NO: 40 for QTL6.1),this encompasses also the SNP genotype in variants of the genomicsequence, i.e. the SNP genotype in a genomic sequence comprising atleast 85%, 90%, 95%, 98%, 99% sequence identity or more to the sequencereferred to (selected from SEQ ID NO: 1 to SEQ ID NO: 26 for QTL2.1 andSEQ ID NO: 27 to 40 for QTL6.1). Thus any reference herein to any one ofSEQ ID NO: 1 to 40 in one aspect also encompasses a variant of any oneof SEQ ID NO: 1 to 40, said variant comprising at least 85%, 90%, 95%,98%, 99% sequence identity or more to said sequence. When referringherein to a SNP genotype at a specific position, e.g. at nucleotide 75of SEQ ID NO: 1, “or of a sequence comprising at least 90%, 91%, 92%,93%, 94%, 95%, 96%, 97%, 98% or 99% sequence identity to the SEQ ID NO”,this means that the SNP genotype is present in a variant sequence at anucleotide corresponding to the same nucleotide (e.g. corresponding tonucleotide 75 of SEQ ID NO: 1) in the variant sequence, i.e. in asequence comprising at least 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%or 99% sequence identity to the mentioned SEQ ID NO. It may for examplebe that the variant sequence is one or a few nucleotides shorter, butwhen one pairwise aligns the variant sequence with the mentioned SEQ IDNO, one can see which nucleotide of the variant sequence corresponds tothe same nucleotide. In the variant sequence this may for example benucleotide number 76 or 74 of that variant sequence which corresponds tonucleotide 75 of the mentioned sequence.

“Yield” or “fruit yield” or “average yield” refers to the average numberof fruits per plant (FrPP) and/or the average fruit weight (grams) perplant (GrPP). This is determined for each plant line, hybrid or varietygrown under the same conditions (e.g. the line, hybrid or variety withthe QTL and the control, e.g. the genetic control, without QTL) and theaverage FrPP and/or GrPP of each line, hybrid or variety is calculated.Depending on the type of cucumber, the fruit yield is measured indifferent ways. So, for example, types which produce fruits continuouslyover a certain period of time, such as fresh market types (e.g. longcucumber types such as the European greenhouse cucumber, mini- ormidi-types), fruits are harvested when they reach marketable size andharvesting is done over a specified period referred to as ‘harvestperiod’ (e.g. the harvest period starts when the first fruits reachmarketable size and may be at least 10, 11, 12 or more weeks long). Sofor example the average FrPP and/or GrPP per line is measured per dayand is cumulated for all days at the end of the harvest period tocalculate the cumulative FrPP and/or GrPP for each line or variety (seealso the Examples). “Marketable size” refers to fruits that are longenough and heavy enough to be marketed. Thus, fruits of marketable sizeare harvested at a time point which is optimal or near optimal formarketing and sale of the fruit. For long cucumber types, such as theEuropean greenhouse cucumber, marketable size is reached when a fruit isat least about 26 or 27 cm long and has a minimum weight of 250 grams.For cucumbers types which are harvested at a single time point only,such as pickling cucumbers, “yield” or “fruit yield” or “average yield”refers to the average number of fruits of equal to or above 1.5 cmdiameter per plant (FrPP) and/or the average fruit weight (grams) offruits which are equal to or above 1.5 cm diameter per plant (GrPP) at asingle harvest time-point. The single harvest time-point is in line withgrowers practice and chosen to maximize the number of fruits having adiameter between 1.5 cm and 5.0 cm. Depending on the desired fruit size,the time-point is generally reached when about 5%, about 10%, about 15%or about 20% of the fruits are oversized, (i.e. have a fruit diameter of5.0 cm or more). Harvest is either by hand or by machine harvest. Thus,in one aspect all fruits per plant are harvested and only the ones witha diameter of at least 1.5 cm are counted and/or weighed (i.e. allfruits with a diameter of at least 1.5 cm are counted and/or weighed,including oversized fruits).

An “increased fruit yield” or a “significantly increased fruit yield”refers to a cultivated cucumber plant line, hybrid or variety comprisingan introgression fragment on chromosome 2 and/or 6, comprising QTL2.1and/or QTL6.1, having (due to the QTL) a statistically significantlyhigher average number of fruits per plant (FrPP) and/or a significantlyhigher average fruit weight per plant (GrPP) compared to the control(e.g. the genetic control) plant lacking the introgression fragment onchromosome 2 and 6, when grown in yield experiments under the sameenvironmental conditions. Preferably trials are carried out in severalreplicates (2, 3, or preferably 3, 4, 5, 6, 7, 8, or more) withsufficient plants (e.g. at least 8, 9, 10, 15, 20, 30, 40, or moreplants per line) comprising the introgression fragment on chromosome 2and/or 6 and control plants lacking the introgression fragment onchromosome 2 and 6 (preferably genetic controls). “Control” is acultivated cucumber breeding line, hybrid or variety lacking theintrogression fragments. “Genetic control” is a cultivated cucumberbreeding line, variety or hybrid which has the same or very similarcultivated genome as the cucumber plant comprising the introgression onchromosome 2 and/or 6 except that it lacks the introgressions onchromosome 2 and 6, i.e. chromosome 2 and 6 are “wild type”, i.e.cultivated cucumber genome. For example, seeds deposited under accessionnumber NCIMB42545 are BC1S3 seeds comprising QTL2.1 and QTL6.1 inhomozygous form (but lacking QTL2.2) in an elite long cucumber breedingline. A suitable genetic control are seeds deposited under NCIMB42345,lacking QTL2.1 and QTL6.1.

The term “marker assay” refers to a molecular marker assay which can beused to test whether on cultivated C. sativus var. sativus chromosome 2and/or 6 an introgression from a wild relative of cucumber is presentwhich introgression fragment comprises the yield QTL2.1 or QTL6.1 (orwhether a wild relative of cucumber comprises the QTL2.1 or QTL6.1, or avariant thereof, in its genome), by determining the genotype of any oneor more markers linked to the QTL2.1 or to QTL6.1, e.g. the genotype ofone or more SNP markers selected from SNP_01 to SNP_26 for QTL2.1 or thegenotype of one or more SNP markers selected from SNP_27 to SNP_40 forQTL6.1, and/or any wild relative of cucumber genome-specific markerin-between SNP markers SNP_01 and SNP_26 on chromosome 2 (i.e. in thephysical region starting at 5.0 Mb to 11.0 Mb of chromosome 2) or inbetween SNP_27 and SNP_40 on chromosome 6 (i.e. in the physical regionstarting 25.0 Mb to 29.0 Mb of chromosome 2), and/or within 7 cM orwithin 5 cM, 3 cM, 2 cM, 1 cM of any one of these markers, and/or within5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb, 0.1 Mb, 50 kb, 20 kb, 10 kb, 5 kb, 2 kb,1 kb or less of any one of these markers. A marker “in between” twomarkers is physically located in between the markers on the chromosome.

The SNP markers provided herein, i.e. SNP_01 to SNP_26 for chromosome 2and SNP_27 to SNP_40 for chromosome 6, are located in the given order onthe introgression fragment. “Consecutive” markers refers to markers inthe same consecutive order, so e.g. two consecutive markers may beSNP_01 and SNP_02; SNP_02 and SNP_03; SNP_03 and SNP_04, etc. and threeconsecutive markers may be SNP_01 and SNP_02 and SNP_03; SNP_02 andSNP_03 and SNP_04; etc.

“Average” or “mean” refers herein to the arithmetic mean and both termsare used interchangeably. The term “average” or “mean” thus refers tothe arithmetic mean of several measurements. The skilled personunderstands that the phenotype of a plant line or variety depends tosome extent on growing conditions and that, therefore, arithmetic meansof at least 8, 9, 10, 15, 20, 30, 40, 50 or more plants (or plant parts)are measured, preferably in randomized experimental designs with severalreplicates and suitable control plants grown under the same conditionsin the same experiment. “Statistically significant” or “statisticallysignificantly” different or “significantly” different refers to acharacteristic of a plant line or variety that, when compared to asuitable control (e.g. the genetic control) show a statisticallysignificant difference in that characteristic (e.g. the p-value is lessthan 0.05, p<0.05, using ANOVA) from the mean of the control.

A “recombinant chromosome” refers to a chromosome having a new geneticmakeup arising through crossing-over between homologous chromosomes,e.g. a “recombinant chromosome 2” or a “recombinant chromosome 6”, i.e.a chromosome 2 or 6 which is not present in either of the parent plantsand arose through a rare double crossing-over event between homologouschromosomes of a chromosome 2 or 6 pair. Herein, for example,recombinant cucumber chromosome 2 is provided comprising anintrogression from a wild relative of cucumber, which comprises a QTLthat enhances fruit yield and recombinant cucumber chromosome 6 isprovided comprising an introgression from a wild relative of cucumber,which comprises a QTL that enhances fruit yield, especially when grownunder cool temperatures. QTL6.1 can, therefore, also be referred to as acold tolerance QTL, or chilling tolerance QTL, as it enhances yieldunder cold stress.

The term “traditional breeding techniques” encompasses herein crossing,backcrossing, selfing, selection, double haploid production, embryorescue, protoplast fusion, marker assisted selection, mutation breedingetc., all as known to the breeder (i.e. methods other than geneticmodification/transformation/transgenic methods), by which, for example,a recombinant chromosome 2 or 6 can be obtained, identified and/ortransferred.

“Backcrossing” refers to a breeding method by which a (single) trait,such as a yield QTL, can be transferred from an inferior geneticbackground (e.g. a wild cucumber or wild relative of cucumber; alsoreferred to as “donor”) into a superior genetic background (alsoreferred to as “recurrent parent”), e.g. cultivated cucumber. Anoffspring of a cross (e.g. an F1 plant obtained by crossing a wildcucumber or wild relative of cucumber with a cultivated cucumber; or anF2 plant or F3 plant, etc., obtained from selfing the F1) is“backcrossed” to the parent with the superior genetic background, e.g.to the cultivated parent. After repeated backcrossing, the trait of theinferior genetic background will have been incorporated into thesuperior genetic background.

“Marker assisted selection” or “MAS” is a process of using the presenceof molecular markers, which are genetically linked to a particular locusor to a particular chromosome region (e.g. introgression fragment), toselect plants for the presence of the specific locus or region(introgression fragment). For example, a molecular marker geneticallyand physically linked to a yield QTL, can be used to detect and/orselect cucumber plants comprising the yield QTL on chromosome 2 and/or6. The closer the genetic linkage of the molecular marker to the locus(e.g. about 7 cM, 6 cM, 5 cM, 4 cM, 3 cM, 2 cM, 1 cM, 0.5 cM or less),the less likely it is that the marker is dissociated from the locusthrough meiotic recombination. Likewise, the closer two markers arelinked to each other (e.g. within 7 cM or 5 cM, 4 cM, 3 cM, 2 cM, 1 cMor less) the less likely it is that the two markers will be separatedfrom one another (and the more likely they will co-segregate as a unit).

A marker “within 7 cM or within 5 cM, 3 cM, 2 cM, or 1 cM” of anothermarker refers to a marker which genetically maps to within the 7 cM or 5cM, 3 cM, 2 cM, or 1 cM region flanking the marker (i.e. either side ofthe marker). Similarly, a marker within 5 Mb, 3 Mb, 2.5 Mb, 2 Mb, 1 Mb,0.5 Mb, 0.4 Mb, 0.3 Mb, 0.2 Mb, 0.1 Mb, 50 kb, 20 kb, 10 kb, 5 kb, 2 kb,1 kb or less of another marker refers to a marker which is physicallylocated within the 5 Mb, 3 Mb, 2.5 Mb, 2 Mb, 1 Mb, 0.5 Mb, 0.4 Mb, 0.3Mb, 0.2 Mb, 0.1 Mb, 50 kb, 20 kb, 10 kb, 5 kb, 2 kb, 1 kb or less, ofthe genomic DNA region flanking the marker (i.e. either side of themarker).

“LOD-score” (logarithm (base 10) of odds) refers to a statistical testoften used for linkage analysis in animal and plant populations. The LODscore compares the likelihood of obtaining the test data if the two loci(molecular marker loci and/or a phenotypic trait locus) are indeedlinked, to the likelihood of observing the same data purely by chance.Positive LOD scores favor the presence of linkage and a LOD scoregreater than 3.0 is considered evidence for linkage. A LOD score of +3indicates 1000 to 1 odds that the linkage being observed did not occurby chance.

“Vegetative propagation”, “vegetative reproduction” or “clonalpropagation” are used interchangeably herein and mean the method oftaking part of a plant and allowing that plant part to form at leastroots where plant part is, e.g., defined as or derived from (e.g. bycutting of) leaf, pollen, embryo, cotyledon, hypocotyl, cells,protoplasts, meristematic cell, root, root tip, pistil, anther, flower,shoot tip, shoot, stem, fruit, petiole, etc. When a whole plant isregenerated by vegetative propagation, it is also referred to as avegetative propagation. In one aspect propagation by grafting, e.g. ascion onto a rootstock, is included herein.

“Cell culture” or “tissue culture” refers to the in vitro culture ofcells or tissues of a plant.

“Regeneration” refers to the development of a plant from cell culture ortissue culture or vegetative propagation.

“Non-propagating cell” refers to a cell which cannot be regenerated intoa whole plant.

“Transgene” or “chimeric gene” refers to a genetic locus comprising aDNA sequence, such as a recombinant gene, which has been introduced intothe genome of a plant by transformation, such as Agrobacterium mediatedtransformation. A plant comprising a transgene stably integrated intoits genome is referred to as “transgenic plant”.

An “isolated nucleic acid sequence” or “isolated DNA” refers to anucleic acid sequence which is no longer in the natural environment fromwhich it was isolated, e.g. the nucleic acid sequence in a bacterialhost cell or in the plant nuclear or plastid genome. When referring to a“sequence” herein, it is understood that the molecule having such asequence is referred to, e.g. the nucleic acid molecule.

A “host cell” or a “recombinant host cell” or “transformed cell” areterms referring to a new individual cell (or organism) arising as aresult of at least one nucleic acid molecule, having been introducedinto said cell. The host cell is preferably a plant cell or a bacterialcell. The host cell may contain the nucleic acid as anextra-chromosomally (episomal) replicating molecule, or comprises thenucleic acid integrated in the nuclear or plastid genome of the hostcell, or as introduced chromosome, e.g. minichromosome.

“Sequence identity” and “sequence similarity” can be determined byalignment of two peptide or two nucleotide sequences using global orlocal alignment algorithms. Sequences may then be referred to as“substantially identical” or “essentially similar” when they areoptimally aligned by for example the programs GAP or BESTFIT or theEmboss program “Needle” (using default parameters, see below) share atleast a certain minimal percentage of sequence identity (as definedfurther below). These programs use the Needleman and Wunsch globalalignment algorithm to align two sequences over their entire length,maximizing the number of matches and minimises the number of gaps.Generally, the default parameters are used, with a gap creationpenalty=10 and gap extension penalty=0.5 (both for nucleotide andprotein alignments). For nucleotides the default scoring matrix used isDNAFULL and for proteins the default scoring matrix is Blosum62(Henikoff & Henikoff, 1992, PNAS 89, 10915-10919). Sequence alignmentsand scores for percentage sequence identity may for example bedetermined using computer programs, such as EMBOSS as available on theworld wide web under ebi.ac.uk/Tools/psa/emboss_needle/). Alternativelysequence similarity or identity may be determined by searching againstdatabases such as FASTA, BLAST, etc., but hits should be retrieved andaligned pairwise to compare sequence identity. Two proteins or twoprotein domains, or two nucleic acid sequences have “substantialsequence identity” if the percentage sequence identity is at least 85%,90%, 95%, 98%, 99% or more (e.g. at least 99.1, 99.2 99.3 99.4, 99.5,99.6, 99.7, 99.8, 99.9 or more (as determined by Emboss “needle” usingdefault parameters, i.e. gap creation penalty=10, gap extensionpenalty=0.5, using scoring matrix DNAFULL for nucleic acids an Blosum62for proteins).

When reference is made to a nucleic acid sequence (e.g. DNA or genomicDNA) having “substantial sequence identity to” a reference sequence orhaving a sequence identity of at least 80%, e.g. at least 85%, 90%, 95%,98% or 99% nucleic acid sequence identity to a reference sequence, inone embodiment said nucleotide sequence is considered substantiallyidentical to the given nucleotide sequence and can be identified usingstringent hybridisation conditions. In another embodiment, the nucleicacid sequence comprises one or more mutations compared to the givennucleotide sequence but still can be identified using stringenthybridisation conditions.

“Stringent hybridisation conditions” can be used to identify nucleotidesequences, which are substantially identical to a given nucleotidesequence. Stringent conditions are sequence dependent and will bedifferent in different circumstances. Generally, stringent conditionsare selected to be about 5° C. lower than the thermal melting point (Tm)for the specific sequences at a defined ionic strength and pH. The Tm isthe temperature (under defined ionic strength and pH) at which 50% ofthe target sequence hybridises to a perfectly matched probe. Typicallystringent conditions will be chosen in which the salt concentration isabout 0.02 molar at pH 7 and the temperature is at least 60° C. Loweringthe salt concentration and/or increasing the temperature increasesstringency. Stringent conditions for RNA-DNA hybridisations (Northernblots using a probe of e.g. 100 nt) are for example those which includeat least one wash in 0.2×SSC at 63° C. for 20 min, or equivalentconditions. Stringent conditions for DNA-DNA hybridisation (Southernblots using a probe of e.g. 100 nt) are for example those which includeat least one wash (usually 2) in 0.2×SSC at a temperature of at least50° C., usually about 55° C., for 20 min, or equivalent conditions. Seealso Sambrook et al. (1989) and Sambrook and Russell (2001).

“Fine-mapping” refers to methods by which the position of a QTL can bedetermined more accurately (narrowed down) and by which the size of theintrogression fragment comprising the QTL is reduced. For example NearIsogenic Lines for the QTL (QTL-NILs) can be made, which containdifferent, overlapping fragments of the introgression fragment within anotherwise uniform genetic background of the recurrent parent. Such linescan then be used to map on which fragment the QTL is located and toidentify a line having a shorter introgression fragment comprising theQTL.

DETAILED DESCRIPTION

The present invention relates to a cultivated Cucumis sativus var.sativus plant comprising one or two yield QTLs, on chromosome 2 and/orchromosome 6, introgressed from a wild relative of cucumber. Thus, theincreased yield is conferred by an introgression fragment on cultivatedcucumber chromosome 2 (comprising QTL2.1 or a variant thereof) and/or onchromosome 6 (comprising QTL6.1 or a variant thereof), wherein saidintrogression fragment is from a wild relative of cucumber. It is notedthat QTL2.1 and QTL6.1 enhance fruit yield on their own, but can also becombined in a single plant. Stacking both QTLs is an advantage, astogether they ensure that the yield increase is attained under differentcultivation conditions.

When reference is made herein to an introgression fragment on chromosome2 comprising a positive yield QTL this encompasses various sizes ofintrogression fragments, e.g. the fragment as found in NCIMB42545comprising the SNP genotype of the wild cucumber relative for all SNPmarkers (SNP_01 to SNP_26, or any marker in between these, for thefragment on chromosome 2), but also smaller introgression fragments(comprising the SNP genotype of the wild cucumber relative of cucumberfor less than the 26 SNP markers such as only e.g. 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25of the SNP markers), where however the fragment retains QTL2.1 or avariant thereof, i.e. it still confers significantly enhanced yield(compared to the control, e.g. the genetic control) when theintrogression fragment is in heterozygous or homozygous form in thecultivated cucumber genome.

Thus, in one aspect a cultivated cucumber plant is provided comprisingan introgression fragment from a wild relative of cucumber, wherein theintrogression fragment comprises QTL2.1, or a variant thereof, andwherein the introgression fragment comprises all or part of the regionstarting at nucleotide (or base) 5,502,468 of chromosome 2 and ending atnucleotide (or base) 10,882,440 of chromosome 2. In other words, all orpart of the region starting at nucleotide 5,502,468 of chromosome 2 andending at nucleotide 10,882,440 of chromosome 2 is, in one aspect, froma wild relative of cucumber and comprises QTL2.1 or a variant thereof.Which sub-region contains QTL2.1 can be identified by e.g. fine-mapping.So, for example if QTL2.1 is found to be in between SNP_01 and SNP_10,then the plant of the invention only needs to comprise the introgressionregion starting at nucleotide 5,502,468 of chromosome 2 (SNP_01) andending at nucleotide 7, 509,399 (SNP_10) of chromosome 2.

In one aspect QTL2.1 (or a variant thereof) is located in-between markerSNP_01 in SEQ ID NO: 1 (or in a variant sequence of SEQ ID NO: 1) andmarker SNP_26 in SEQ ID NO: 26 (or in a variant sequence of SEQ ID NO:26). In another aspect QTL2.1 (or a variant thereof) is locatedin-between marker SNP_01 in SEQ ID NO: 1 (or in a variant sequence ofSEQ ID NO: 1) and marker SNP_10 in SEQ ID NO: 10 (or in a variantsequence of SEQ ID NO: 10). In a further aspect QTL2.1 (or a variantthereof) is located in-between marker SNP_10 in SEQ ID NO: 10 (or in avariant sequence of SEQ ID NO: 10) and marker SNP_20 in SEQ ID NO: 20(or in a variant sequence of SEQ ID NO: 20). In a further aspect QTL2.1(or a variant thereof) is located in-between marker SNP_20 in SEQ ID NO:20 (or in a variant sequence of SEQ ID NO: 20) and marker SNP_26 in SEQID NO: 26 (or in a variant sequence of SEQ ID NO: 26). In still afurther aspect QTL2.1 (or a variant thereof) is located in-betweenmarker SNP_06 in SEQ ID NO: 06 (or in a variant sequence of SEQ ID NO:06) and marker SNP_23 in SEQ ID NO: 23 (or in a variant sequence of SEQID NO: 23).

In another aspect the introgression fragment of the invention(comprising QTL2.1 or a variant thereof) is a fragment comprising asmaller fragment (part) of the region starting at 5,502,468 bp andending at 10,882,440 bp of chromosome 2, e.g. having a size of e.g. 5.0Mb, 4.0 Mb, 3.0 Mb, 2.5 Mb, 2 Mb, 1 Mb, 0.5 Mb, 100 kb, 50 kb, 35 kb, 30kb, 20 kb, or less and comprising the QTL or a variant thereof. In oneaspect the part is at least 5 kb, 10 kb, 20 kb in size, or more. Thesmaller fragment retains QTL2.1, i.e. the smaller fragment confers anincrease in cucumber fruit yield, e.g. as described for the wholeintrogression fragment.

In one aspect the cultivated cucumber plant of the invention comprisesan introgression fragment from a wild cucumber or a wild relative ofcucumber, which introgression fragment comprises QTL2.1 or a variantthereof, wherein the introgression fragment comprises all of part of theregion starting at 5.5 Mb and ending at 10.9 Mb of the physicalchromosome 2; in another aspect starting at 5.0 Mb and ending at 10.89Mb.

In one aspect the introgression fragment on chromosome 2 comprisingQTL2.1 is obtainable by crossing a plant grown from NCIMB42545 withanother cucumber plant, especially a cultivated cucumber plant, in oneaspect a long cucumber type.

During the QTL mapping program, QTL2.1 was initially not recognized, asanother QTL nearby QTL2.1 on chromosome 2 had a negative effect on theaverage fruit weight per plant, and the peak of both QTLs were so closeto each other that separation of one from the other seemed not possible(see FIG. 1). This negative region of the introgression fragment onchromosome could surprisingly however be removed by recombination, i.e.by removing parts of the wild relative of cucumber region furtherdownstream of SNP_26. Thus in one aspect the chromosome region betweenSNP_26 (physical position base 10,882,440) and the end of chromosome 2(i.e. up to base 23,174,625) does not comprise a negative yield QTL(QTL2.2) which reduced fruit length from the wild relative of cucumberand is preferably cultivated cucumber genome. Thus, the instantinvention provides plants comprising QTL2.1, which have enhancedcumulative fruit yield compared to the genetic control (lacking QTL2.1)without reducing the average fruit length, i.e. average fruit length isnot different from the average fruit length of the genetic control.

When reference is made herein to an introgression fragment on chromosome6 having a yield QTL this encompasses various sizes of introgressionfragments, e.g. the fragment as found in NCIMB42545 comprising the SNPgenotype of the wild cucumber relative for all SNP markers (SNP_27 toSNP_40, or any marker in between these, for the fragment on chromosome6), but also smaller introgression fragments (comprising the SNPgenotype of the wild cucumber relative for less than these 14 SNPmarkers such as only e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13 ofthe SNP markers), where however the fragment retains QTL6.1 or a variantthereof, i.e. it still confers significantly enhanced yield (compared tothe control, e.g. the genetic control) when the introgression fragmentis in heterozygous or homozygous form in the cultivated cucumber genome.

Thus, in one aspect a cultivated cucumber plant is provided comprisingan introgression fragment from a wild relative of cucumber, wherein theintrogression fragment comprises QTL6.1, or a variant thereof, andwherein the introgression fragment comprises all or part of the regionstarting at nucleotide (or base) 25,519,964 of chromosome 6 and endingat nucleotide (or base) 28,300,913 of chromosome 6. In other words, allor part of the region starting at nucleotide 25,519,964 of chromosome 6and ending at nucleotide 28,300,913 of chromosome 6 is, in one aspect,from a wild relative of cucumber and comprises QTL6.1 or a variantthereof. Which sub-region contains QTL6.1 can be identified by e.g.fine-mapping. So, for example if QTL6.1 is found to be in between SNP_27and SNP_33, then the plant of the invention only needs to comprise theintrogression region starting at nucleotide 25,519,964 of chromosome 6(SNP_27) and ending at nucleotide 26,501,889 (SNP_33) of chromosome 6.

In one aspect QTL6.1 (or a variant thereof) is located in-between markerSNP_27 in SEQ ID NO: 27 (or in a variant sequence of SEQ ID NO: 27) andmarker SNP_40 in SEQ ID NO: 40 (or in a variant sequence of SEQ ID NO:40). In another aspect QTL6.1 (or a variant thereof) is locatedin-between marker SNP_27 in SEQ ID NO: 27 (or in a variant sequence ofSEQ ID NO: 27) and marker SNP_33 in SEQ ID NO: 33 (or in a variantsequence of SEQ ID NO: 33). In yet another aspect QTL6.1 (or a variantthereof) is located in-between marker SNP_33 in SEQ ID NO: 33 (or in avariant sequence of SEQ ID NO: 33) and marker SNP_40 in SEQ ID NO: 40(or in a variant sequence of SEQ ID NO: 40). In even a further aspectQTL6.1 (or a variant thereof) is located in-between marker SNP_29 in SEQID NO: 29 (or in a variant sequence of SEQ ID NO: 29) and marker SNP_38in SEQ ID NO: 38 (or in a variant sequence of SEQ ID NO: 38).

In another aspect the introgression fragment of the invention(comprising QTL6.1 or a variant thereof) is a fragment comprising asmaller fragment (part) of the region starting at 25,519,964 bp andending at 28,300,913 bp of chromosome 6, e.g. having a size of e.g. 2.8Mb, 1.9 Mb, 1 Mb, 0.5 Mb, 100 kb, 50 kb, 35 kb, 30 kb, 20 kb, or lessand comprising the QTL or a variant thereof. In one aspect the part isat least 5 kb, 10 kb, 20 kb in size, or more. The smaller fragmentretains QTL6.1, i.e. the smaller fragment confers an increase incucumber fruit yield, e.g. as described for the whole introgressionfragment.

In one aspect the cultivated cucumber plant of the invention comprisesan introgression fragment from a wild cucumber or a wild relative ofcucumber, which introgression fragment comprises QTL6.1 or a variantthereof, wherein the introgression fragment comprises all of part of theregion starting at 26 Mb and ending at 28.5 Mb or at the end of thephysical chromosome 6, i.e. at 29.07 Mb; in another aspect starting at25.6 Mb and ending at 28.5 Mb or at the end of chromosome 6.

In one aspect the introgression fragment on chromosome 6 comprisingQTL6.1 is obtainable by crossing a plant grown from NCIMB42545 withanother cucumber plant, especially a cultivated cucumber plant, in oneaspect a long cucumber type.

When referring to the SNP markers herein, which are indicative of thepresence of the introgression fragment on chromosome 2 or 6 (and eitherof the increased yield QTLs present on the introgression fragment), itis understood that the SNP genotype which is indicative of theintrogression fragment is referred to, i.e. the SNP genotype as providedin Table 7 herein below for chromosome 2 and in Table 8 for chromosome6. It is noted that the SNP marker genotype can distinguish between theintrogression fragment being in homozygous or heterozygous form, asshown in the Table. In homozygous form the nucleotide is identical,while in heterozygous form the nucleotide is not identical. The SNPgenotype of the ‘wild type’ chromosome lacking the introgressionfragment is the other genotype, also listed in Table 7 and 8 (undergenotype of recurrent parent). So, e.g. the genotype of SNP_01indicative of the introgression fragment comprising QTL2.1 is ‘CC’(QTL2.1/QTL2.1) or ‘CT’ (QTL2.1/wt) while the SNP genotype indicative ofthe wild type/genetic control/control (lacking the introgressionfragment) is ‘TT’ (wt/wt). Thus, when referring to a plant or plant part(e.g. cell) comprising the introgression fragment in homozygous orheterozygous form, it is understood that the SNP markers linked to theintrogression fragment have the corresponding SNP genotype.

So in one aspect, a cultivated Cucumis sativus var. sativus plant isprovided comprising an introgression fragment on chromosome 2 and/or 6in homozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield compared to the cucumberplant lacking the introgression fragment on chromosome 2 and 6, e.g. thegenetic control or control variety, when grown under the sameconditions.

The increase in cucumber fruit yield is phenotypically expressed as a(statistically) significantly higher average number of fruits per plant(FrPP) of the cultivated cucumber plant line or variety comprising theintrogression fragment on chromosome 2 and/or 6 in homozygous orheterozygous form compared to the control line or variety lacking theintrogression fragment on chromosome 2 and 6 (e.g. the genetic control)when grown under the same environment and/or a significantly higheraverage fruit weight per plant (GrPP) of the plant line or varietycomprising the introgression fragment compared to the genetic controlline or variety lacking the introgression fragment when grown under thesame environment.

Fruit yield (total average FrPP and/or GrPP) is preferably in thecucumber plant comprising QTL2.1 (or a variant) and/or QTL6.1 (or avariant) at least 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%,15% higher than in the control, preferably than in the genetic control,when grown under the same environment.

The plants of the invention, therefore, comprise a genome of cultivatedcucumber, with at least one or two recombinant chromosomes 2 (i.e.heterozygous or homozygous) and/or with at least one or two recombinantchromosomes 6 (i.e. heterozygous or homozygous). The recombinantchromosomes comprise a fragment of a wild relative of cucumber, which iseasily distinguishable from the cultivated cucumber genome by molecularmarker analysis, whole genome sequencing, chromosome painting andsimilar techniques.

In one aspect the introgression fragment on chromosome 2 is from a wildrelative of cucumber, comprises the positive yield QTL2.1, or a variantthereof, and comprises all or part of the region starting at nucleotide5,502,468 and ending at nucleotide 10,882,440 of the chromosome. Thus,the introgression fragment comprises the yield QTL2.1 or a variantthereof and one or more or all (e.g. 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26) SNP markers ofthe wild relative of cucumber selected from SNP_01 to SNP_26 as shown inTable 7.

In one aspect the introgression fragment on chromosome 6 is from a wildrelative of cucumber, comprises the positive yield QTL6.1, or a variantthereof, and comprises all or part of the region starting at nucleotide25,519,964 and ending at nucleotide 28,300,913 of the chromosome. Thus,the introgression fragment comprises the yield QTL6.1 or a variantthereof and one or more or all (e.g. 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,13, 14) SNP markers of the wild relative of cucumber selected fromSNP_27 to SNP_40.

In one aspect the presence of the introgression fragment on chromosomes2 or 6 in the genome of the plant or plant cell or plant tissue (or inthe DNA extracted therefrom) is detectable by a molecular marker assaywhich detects one or more molecular markers of the introgressionfragment. However, as mentioned, other techniques may be used, e.g. theSNP genotype of the markers may also be determined by sequencing or byusing alternative markers located in between the SNP markers providedherein or within 7 cM, or within 5 cM, of a marker provided herein; orwithin 5 Mb, 3 Mb, 2.5 Mb, 2 Mb, 1 Mb, 0.5 Mb, 0.4 Mb, 0.3 Mb, 0.2 Mb,0.1 Mb, 50 kb, 20 kb, 10 kb, 5 kb, 2 kb, 1 kb or less of a markerprovided herein.

When reference is made herein to one or more molecular markers being“detectable” by a molecular marker assay, this means of course that theplant or plant part comprises the one or more markers in its genome, asthe marker would otherwise not be detectable.

Cucumber Plants Comprising an Introgression Fragment on Chromosome 2(Yield QTL 2.1)

QTL2.1 is located in the region between SNP_01 in SEQ ID NO: 1 (or in avariant thereof) and SNP_26 in SEQ ID NO: 26 (or a variant thereof).

Therefore, in one aspect a cultivated Cucumis sativus var. sativus plantis provided comprising an introgression fragment on chromosome 2 inhomozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay (i.e. the plant comprises one or more molecular markers) whichdetects at least 1, preferably at least 2 or 3, or at least 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or26 of the markers selected from the group consisting of:

-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_01 in SEQ ID NO: 1 (or in a variant thereof);-   b) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_02 in SEQ ID NO: 2 (or in a variant thereof);-   c) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_03 in SEQ ID NO: 3 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_04 in SEQ ID NO: 4 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_05 in SEQ ID NO: 5 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_06 in SEQ ID NO: 6 (or in a variant thereof);-   g) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_07 in SEQ ID NO: 7 (or in a variant thereof);-   h) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_08 in SEQ ID NO: 8 (or in a variant thereof);-   i) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_09 in SEQ ID NO: 9 (or in a variant thereof);-   j) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   k) the GG or AG genotype for the Single Nucleotide Polymorphism    marker SNP_11 in SEQ ID NO: 11 (or in a variant thereof);-   l) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_12 in SEQ ID NO: 12 (or in a variant thereof);-   m) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_13 in SEQ ID NO: 13 (or in a variant thereof);-   n) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_14 in SEQ ID NO: 14 (or in a variant thereof);-   o) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_15 in SEQ ID NO: 15 (or in a variant thereof);-   p) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_16 in SEQ ID NO: 16 (or in a variant thereof);-   q) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_17 in SEQ ID NO: 17 (or in a variant thereof);-   r) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_18 in SEQ ID NO: 18 (or in a variant thereof);-   s) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_19 in SEQ ID NO: 19 (or in a variant thereof);-   t) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   u) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_21 in SEQ ID NO: 21 (or in a variant thereof);-   v) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_22 in SEQ ID NO: 22 (or in a variant thereof);-   w) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_23 in SEQ ID NO: 23 (or in a variant thereof);-   x) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_24 in SEQ ID NO: 24 (or in a variant thereof);-   y) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_25 in SEQ ID NO: 25 (or in a variant thereof);-   z) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_26 in SEQ ID NO: 26 (or in a variant thereof);-   aa) any wild relative of cucumber genome-specific marker in between    marker SNP_01 and SNP_26.

As mentioned previously, when referring to a SNP in a variant sequence,that variant sequence comprises at least 85% sequence identity with thementioned sequence.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25 or 26 markers are selected from the group consisting ofmarkers a) to z). In one aspect said at least 1, preferably at least 2or 3, or at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,19, 20, 21, 22, 23, 24, 25 or 26 markers are consecutive markers.

As mentioned, the skilled person can also develop other molecularmarkers, e.g. a wild-relative of cucumber genome-specific markerin-between marker SNP_01 and SNP_26 and/or within 7 cM or within 5 cM ofany one of SNP_01 to SNP_26, and/or within 5 Mb, 3 Mb, 2.5 Mb, 2 Mb, 1Mb, 0.5 Mb, 0.4 Mb, 0.3 Mb, 0.2 Mb, 0.1 Mb, 50 kb, 20 kb, 10 kb, 5 kb orless of any one of SNP_01 to SNP_26. Such markers may also be a stretchof nucleotide, CAPS markers, INDELs, etc. The skilled person can, forexample, sequence the introgression fragment found in seeds depositedunder accession number NCIMB42545 and use the sequence information todevelop new markers and marker assays.

In another aspect QTL2.1 is located in the region between SNP_01 in SEQID NO: 1 (or in a variant thereof) and SNP_10 in SEQ ID NO: 10 (or avariant thereof).

Thus, in another aspect a cultivated Cucumis sativus var. sativus plantis provided comprising an introgression fragment on chromosome 2 inhomozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay which detects at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10 of the markers selected from the group consistingof:

-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_01 in SEQ ID NO: 1 (or in a variant thereof);-   b) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_02 in SEQ ID NO: 2 (or in a variant thereof);-   c) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_03 in SEQ ID NO: 3 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_04 in SEQ ID NO: 4 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_05 in SEQ ID NO: 5 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_06 in SEQ ID NO: 6 (or in a variant thereof);-   g) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_07 in SEQ ID NO: 7 (or in a variant thereof);-   h) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_08 in SEQ ID NO: 8 (or in a variant thereof);-   i) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_09 in SEQ ID NO: 9 (or in a variant thereof);-   j) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   k) any wild relative of cucumber genome-specific marker in between    marker SNP_01 and SNP_10.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, or 10 markers are selected from the group consistingof markers a) to j). In one aspect said at least 1, preferably at least2 or 3, or at least 4, 5, 6, 7, 8, 9, or 10 markers are consecutivemarkers.

In yet another aspect QTL2.1 is located in the region between SNP_10 inSEQ ID NO: 10 (or in a variant thereof) and SNP_20 in SEQ ID NO: 20 (ora variant thereof).

Therefore, in a different aspect a cultivated Cucumis sativus var.sativus plant is provided comprising an introgression fragment onchromosome 2 in homozygous or heterozygous form, wherein saidintrogression fragment confers an increase in cucumber fruit yield(compared to the plant lacking the introgression fragment, e.g. thegenetic control) and wherein said introgression fragment is detectableby a molecular marker assay which detects at least 1, preferably atleast 2 or 3, or at least 4, 5, 6, 7, 8, 9, 10 or 11 of the markersselected from the group consisting of:

-   1) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   2) the GG or AG genotype for the Single Nucleotide Polymorphism    marker SNP_11 in SEQ ID NO: 11 (or in a variant thereof);-   3) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_12 in SEQ ID NO: 12 (or in a variant thereof);-   4) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_13 in SEQ ID NO: 13 (or in a variant thereof);-   5) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_14 in SEQ ID NO: 14 (or in a variant thereof);-   6) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_15 in SEQ ID NO: 15 (or in a variant thereof);-   7) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_16 in SEQ ID NO: 16 (or in a variant thereof);-   8) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_17 in SEQ ID NO: 17 (or in a variant thereof);-   9) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_18 in SEQ ID NO: 18 (or in a variant thereof);-   10) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_19 in SEQ ID NO: 19 (or in a variant thereof);-   11) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   12) any wild relative of cucumber genome-specific marker in between    marker SNP_10 and SNP_20.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10 or 11 markers are selected from the groupconsisting of markers 1) to 11). In one aspect said at least 1,preferably at least 2 or 3, or at least 4, 5, 6, 7, 8, 9, 10, or 11markers are consecutive markers.

In another aspect QTL2.1 is located in the region between SNP_20 in SEQID NO: 20 (or in a variant thereof) and SNP_26 in SEQ ID NO: 26 (or avariant thereof).

Therefore in a further aspect a cultivated Cucumis sativus var. sativusplant is provided comprising an introgression fragment on chromosome 2in homozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay which detects at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7 or 8 of the markers selected from the group consisting of:

-   1) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   2) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_21 in SEQ ID NO: 21 (or in a variant thereof);-   3) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_22 in SEQ ID NO: 22 (or in a variant thereof);-   4) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_23 in SEQ ID NO: 23 (or in a variant thereof);-   5) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_24 in SEQ ID NO: 24 (or in a variant thereof);-   6) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_25 in SEQ ID NO: 25 (or in a variant thereof);-   7) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_26 in SEQ ID NO: 26 (or in a variant thereof);-   8) any wild relative of cucumber genome-specific marker in between    marker SNP_20 and SNP_26.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7 or 8 markers are selected from the group consisting ofmarkers 1) to 7). In one aspect said at least 1, preferably at least 2or 3, or at least 4, 5, 6, 7, or 8 markers are consecutive markers.

In even another aspect QTL2.1 is located in the region between SNP_06 inSEQ ID NO: 06 (or in a variant thereof) and SNP_23 in SEQ ID NO: 23 (ora variant thereof).

Thus, in another embodiment a cultivated Cucumis sativus var. sativusplant is provided comprising an introgression fragment on chromosome 2in homozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay which detects at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 of the markersselected from the group consisting of:

-   1) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_06 in SEQ ID NO: 6 (or in a variant thereof);-   2) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_07 in SEQ ID NO: 7 (or in a variant thereof);-   3) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_08 in SEQ ID NO: 8 (or in a variant thereof);-   4) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_09 in SEQ ID NO: 9 (or in a variant thereof);-   5) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   6) the GG or AG genotype for the Single Nucleotide Polymorphism    marker SNP_11 in SEQ ID NO: 11 (or in a variant thereof);-   7) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_12 in SEQ ID NO: 12 (or in a variant thereof);-   8) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_13 in SEQ ID NO: 13 (or in a variant thereof);-   9) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_14 in SEQ ID NO: 14 (or in a variant thereof);-   10) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_15 in SEQ ID NO: 15 (or in a variant thereof);-   11) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_16 in SEQ ID NO: 16 (or in a variant thereof);-   12) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_17 in SEQ ID NO: 17 (or in a variant thereof);-   13) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_18 in SEQ ID NO: 18 (or in a variant thereof);-   14) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_19 in SEQ ID NO: 19 (or in a variant thereof);-   15) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   16) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_21 in SEQ ID NO: 21 (or in a variant thereof);-   17) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_22 in SEQ ID NO: 22 (or in a variant thereof);-   18) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_23 in SEQ ID NO: 23 (or in a variant thereof);-   19) any wild relative of cucumber genome-specific marker in between    marker SNP_06 and SNP_23.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 markers areselected from the group consisting of markers 1) to 18). In one aspectsaid at least 1, preferably at least 2 or 3, or at least 4, 5, 6, 7, 8,9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 markers are consecutivemarkers.

The introgression fragment comprising the QTL may, thus, be large(comprising SNP_01 to SNP_26), or may be smaller and lack markers, butit may still confer enhanced yield on the cultivated cucumber plant,i.e. it can still comprise the yield allele (QTL2.1 or a variant). Suchsmaller introgression fragments are an embodiment of the invention.Plants having smaller introgression fragments which still confer theenhanced yield (i.e. contain the yield allele) can be generated usingknown techniques, such as fine-mapping or similar techniques. Forexample by starting with a plant comprising the introgression fragmentas found in seeds deposited under accession number NCIMB 42545 andcrossing such a plant with another cultivated cucumber plant and selfingthe progeny of said cross, and/or backcrossing the progeny, to generatea population of plants which will contain recombinants having a smallerintrogression fragment on chromosome 2, which fragments still conferenhanced yield in relation to a plant lacking the introgression fragment(such as the genetic control, e.g. plants grown from seeds depositedunder NCIMB42345), e.g. a fragment comprising the wild relative genotypeof markers SNP_01 to SNP_10 (or smaller, e.g. comprising only 9, 8, 7,6, 5, 4, 3, 2 or 1 of the SNP markers), SNP_10 to SNP_20 (or smallere.g. comprising only 10, 9, 8, 7, 6, 5, 4, 3, 2 or 1 of the SNPmarkers), SNP_20 to SNP_26 (or smaller e.g. comprising only 7, 6, 5, 4,3, 2 or 1 of the SNP markers) or SNP_06 to SNP_23 (or smaller e.g.comprising only 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2or 1 of the SNP markers). Marker assays can be used to selectrecombinants and to determine the size of the smaller introgressionfragment. One or more of SNP markers or the wild-relative genotype maybe missing. The cultivated cucumber genotype is then detected for theSNP marker. The yield of plants comprising such a smaller introgressionfragment can then be compared in yield experiments as described herein,i.e. growing a plurality of plants comprising the smaller introgressionfragment in field experiments together with suitable control plants,lacking the introgression fragment. The control plants are preferably agenetic control, such as NCIMB42345. If the average yield remainssignificantly higher than in the control, then the smaller introgressionfragment has retained the QTL2.1.

Alternatively, the same or variant QTL (QTL2.1 or variant QTL2.1) may beintrogressed from a different wild relative of cucumber, wherebyoptionally not all SNP markers disclosed herein are present. Suchalternative wild relative of cucumber sources can be identified usingthe SNP markers provided herein, by screening germplasm (i.e. accessionsof) wild relatives of cucumber using a marker assay to detect thegenotype of markers SNP_01 to SNP_26, or of markers SNP_01 to SNP_10,SNP_10 to SNP_20, SNP_20 to SNP_26, or SNP_06 to SNP_23, or even only asmaller subgroup of these markers (e.g. 2, 3, 4, 5, 6, 7, 8, or more).Plants comprising the same or variant QTL2.1 from other sources are alsoan embodiment of the invention. As long as at least one or more (or all)of the SNPs of SNP_01 to SNP_26, or of the SNPs of SNP_01 to SNP_10, orof the SNPs of SNP_10 to SNP_20, or of the SNPs of SNP_20 to SNP_26, orof the SNPs of SNP_06 to SNP_23 is present, and the plant has theyield-increasing genotype, i.e. the plant comprises QTL2.1 (or a variantthereof). The skilled person can then introgress the QTL2.1 (or avariant thereof) into cultivated cucumber in order to enhance fruityield as described herein and in order to confirm that the QTL enhancesyield when present in cultivated cucumber. For example, QTL2.1 can beintrogressed into a specific breeding line or variety and the line orvariety without the introgression can be used as the genetic control inyield trials.

As described above, in one embodiment the cultivated cucumber plant ofthe invention comprises an introgression fragment comprising at least asubset of SNP markers with the genotype of the wild relative ofcucumber, i.e. at least 1, 2, 3, 4, or 5 markers of SNP_01 to SNP_26, orof SNP_01 to SNP_10, or of SNP_10 to SNP_20, or of SNP_20 to SNP_26, orof SNP_06 to SNP_23. In one aspect the cultivated cucumber plantcomprises all, or all except 1 or 2 markers of SNP_01 to SNP_26, or ofSNP_01 to SNP_10, or of SNP_10 to SNP_20, or of SNP_20 to SNP_26, or ofSNP_06 to SNP_23.

Thus, the introgression fragment (and a cultivated cucumber plant orplant part, e.g., a cell, comprising the introgression fragment) can bedetected in a marker assay by detecting the SNP genotype of theintrogression fragment (i.e. of the wild relative of cucumber germplasm)of one or more or all of the markers above.

Thus, in one aspect, a Quantitative Trait Locus (QTL2.1) was found to bepresent on chromosome 2 of a wild relative of cucumber which, whentransferred (introgressed) into a cultivated cucumber variety orbreeding line, and when present in heterozygous or homozygous form,confers significantly enhanced fruit yield onto the cultivated cucumberplant. The QTL, or the introgression fragment comprising the QTL(comprising the yield allele), is thus dominant, i.e. it is sufficientto have the introgression fragment on one of the chromosomes 2 (onerecombinant chromosome 2), while the homologous chromosome 2 of the pairmay be a (non-recombinant) chromosome 2 of cultivated C. sativus var.sativus lacking the introgression fragment.

Although the present source of the yield QTL is a single, specific wildsource, there are likely other wild relatives of Cucumis accessionswhich comprise QTL2.1 at the same locus on chromosome 2. Such loci maycomprise yield alleles which have slightly different nucleotidesequences, i.e. variants of the allele (QTL) found herein. Such variantQTLs can also be identified and introgressed into cultivated cucumber asdescribed herein, to generate a cultivated cucumber plant comprising agenome of cultivated C. sativus var. sativus and a recombinantchromosome 2, whereby the recombinant chromosome 2 comprises a wildrelative of Cucumis sativus species introgression fragment, whichconfers an enhanced yield phenotype onto the cultivated cucumber plantwhen present in homozygous or heterozygous form. To identify such wildrelatives of cucumber comprising QTL2.1, wild accessions can bescreened, e.g. in a marker assay or by sequence comparison or othermethods, for the presence of one or more of the SNP markers providedherein. The putative yield QTLs (or variant QTLs) can then beintrogressed into cultivated cucumber, e.g. using MAS, i.e. using one ormore (or all) of the SNP markers provided herein to detect and/or selectprogeny plants (e.g. backcross plants) comprising a recombinantchromosome 2. The selected plants, i.e. the cultivated cucumber plantscomprising an introgression fragment on chromosome 2, wherein theintrogression fragment on chromosome 2 is detectable by one or more ofthe SNP markers SNP_01 to SNP_26, one or more of the SNP markers SNP_01to SNP_10, one or more of the SNP markers SNP_10 to SNP_20, one or moreof the SNP markers SNP_20 to SNP_26, or one or more of the SNP markersSNP_06 to SNP_23 (as described elsewhere herein) can then be phenotypedin yield experiments together with the suitable control plants,preferably at least the genetic control, in order to determine whetherthe introgression fragment indeed causes a significant yield increase.

Accessions of wild relatives of cucumber, are obtainable from the USDANational Plant Germplasm System collection or other seed collections,and can thus be screened for the presence of QTL2.1 using e.g. a markerassay as described herein, and accessions comprising one or more of theSNP markers (e.g. at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or all 26 SNP markersindicative of QTL2.1 can be crossed with a cultivated cucumber planthaving normal wild-type, non-recombinant chromosomes 2. The F1 or F2generation (or further generation, such as the F3 or a backcrossgeneration) can then be screened for recombinant plants having theintrogression fragment, or a yield increasing part thereof, using themolecular marker assays described herein.

In one aspect, the introgression fragment is from a wild relative ofcucumber, which belongs to the Indian Cucumber Group, and which istransferred onto chromosome 2 of the Eurasian Cucumber Group, therebycreating a cultivated cucumber plant comprising yield QTL2.1 or avariant thereof. Thus, in one embodiment the introgression fragmentcomprising the yield QTL2.1 is derivable from (or derived from) orobtainable from (or obtained from; or as present in) a wild relative ofcucumber which belongs to the Indian Cucumber Group.

In a specific embodiment, the introgression fragment comprising theyield QTL2.1 is derivable from (or derived from) or obtainable from (orobtained from; or as present in) seeds, a representative sample of whichhas been deposited under accession number NCIMB 42545, or from progenythereof. The progeny may be any progeny which retain the one or more (orall) SNP markers indicative of (and linked to) the QTL, as described.Thus, progeny are not limited to F1 or F2 progeny of the deposit, butcan be any progeny, whether obtained by selfing and/or crossing withanother cucumber plant.

In one embodiment the introgression fragment is identifiable by one ormore of the markers described elsewhere herein, especially markersSNP_01 to SNP_26 for the introgression fragment on chromosome 2, or asubset of markers, such as one or more of the markers selected from SNPmarkers SNP_01 to SNP_10, or from SNP markers SNP_10 to SNP_20, or fromof the SNP markers SNP_20 to SNP_26, or from SNP markers SNP_06 toSNP_23. In one aspect the invention provides a cultivated cucumberplant, having a genome of cultivated (domesticated) cucumber whichcomprises enhanced fruit yield, wherein the enhanced fruit yield isconferred by an introgression fragment on the cultivated cucumberchromosome 2, wherein said introgression fragment is obtained by (orobtainable by) crossing a cultivated plant grown from seeds depositedunder NCIMB 42545 or progeny of this plant (which comprises one or morethe markers disclosed herein linked to the QTL) with a cultivatedcucumber plant. Thus in one aspect the cultivated cucumber plant of theinvention comprises the same introgression fragment and the samerecombinant chromosome 2 as present in NCIMB 42545 (comprising the wildrelative genotype for SNP_01 to SNP_26), or it comprises a shorterfragment of that introgression fragment, whereby the shorter fragmentretains the genetic element conferring enhanced fruit yield (QTL2.1).

Thus in one aspect the invention relates to a plant of the inventioni.e. a cultivated Cucumis sativus var. sativus plant comprising anintrogression fragment from a wild relative of cucumber on chromosome 2in homozygous or heterozygous form and wherein said introgressionfragment is the introgression fragment “as in”/is “identical to”/is “thesame as in” the seeds deposited under number NCIMB 42545, or is ashorter fragment thereof, but still confers enhanced fruit yield due tothe presence of QTL2.1.

In yet another embodiment the invention relates to a plant of theinvention i.e. a cultivated Cucumis sativus var. sativus plantcomprising an introgression fragment from a wild relative of cucumber onchromosome 2, in homozygous or heterozygous form, and wherein saidintrogression fragment is a variant of the introgression fragment foundin seeds deposited under number NCIMB 42545, i.e. it comprises the yieldQTL 2.1, but the genomic sequence may be different. As wild accessionswill be genetically divergent, the genomic sequence of an introgressionfragment comprising QTL2.1 from other wild relatives of cucumber willmost likely not be identical to the genomic sequence as introgressedinto NCIMB42545, and even the yield conferring gene (comprising apromoter, introns and exons) may be divergent in nucleotide sequence,but the function will be the same, i.e. conferring enhanced fruit yield.The divergence can be seen in that certain SNP markers linked to QTL2.1may be commonly found in various accessions, while other SNP markers mayonly be found in specific accessions. So for example not all of SNP_01to SNP_26 may be found in other wild relatives of cucumber. However, theyield enhancing QTL2.1 (comprising e.g. a variant or ortholog of theyield allele) may still be present in such wild accessions. The skilledperson is capable of identifying and introgressing the QTLs 2.1comprising region found in other wild relatives of cucumber intocultivated cucumber, e.g. detecting wild relatives comprising the SNPmarkers or a subset thereof and transferring these SNP markers (orsubset) into a cultivated cucumber line or variety and assessing thefruit yield of the cultivated line or variety compared to the line orvariety lacking the SNP markers (or subset), i.e. lacking theintrogression fragment.

In one embodiment the presence of the introgression fragment, or thechromosome 2 region (or variant or orthologous chromosome 2 region),comprising QTL2.1, is detectable by a molecular marker assay whichdetects at least 1, preferably at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 or more (or all26) Single Nucleotide Polymorphism (SNP) markers selected from the groupconsisting of:

-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_01 in SEQ ID NO: 1 (or in a variant thereof);-   b) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_02 in SEQ ID NO: 2 (or in a variant thereof);-   c) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_03 in SEQ ID NO: 3 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_04 in SEQ ID NO: 4 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_05 in SEQ ID NO: 5 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_06 in SEQ ID NO: 6 (or in a variant thereof);-   g) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_07 in SEQ ID NO: 7 (or in a variant thereof);-   h) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_08 in SEQ ID NO: 8 (or in a variant thereof);-   i) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_09 in SEQ ID NO: 9 (or in a variant thereof);-   j) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   k) the GG or AG genotype for the Single Nucleotide Polymorphism    marker SNP_11 in SEQ ID NO: 11 (or in a variant thereof);-   1) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_12 in SEQ ID NO: 12 (or in a variant thereof);-   m) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_13 in SEQ ID NO: 13 (or in a variant thereof);-   n) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_14 in SEQ ID NO: 14 (or in a variant thereof);-   o) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_15 in SEQ ID NO: 15 (or in a variant thereof);-   p) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_16 in SEQ ID NO: 16 (or in a variant thereof);-   q) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_17 in SEQ ID NO: 17 (or in a variant thereof);-   r) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_18 in SEQ ID NO: 18 (or in a variant thereof);-   s) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_19 in SEQ ID NO: 19 (or in a variant thereof);-   t) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   u) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_21 in SEQ ID NO: 21 (or in a variant thereof);-   v) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_22 in SEQ ID NO: 22 (or in a variant thereof);-   w) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_23 in SEQ ID NO: 23 (or in a variant thereof);-   x) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_24 in SEQ ID NO: 24 (or in a variant thereof);-   y) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_25 in SEQ ID NO: 25 (or in a variant thereof);-   z) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_26 in SEQ ID NO: 26 (or in a variant thereof);-   aa) optionally any wild relative of cucumber genome-specific marker    in between marker SNP_01 and SNP_26.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,23, 24, 25 or 26 markers which are detected are consecutive markers.

Thus, in one embodiment the plants according to the invention compriseat least a Cytosines (C) (i.e. the CC or CT genotype) instead of twoThymine (TT) at nucleotide 75 of SEQ ID NO: 1 (referred to as SNP_01) orat the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:1 (in other words there is aCytosine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO: 2 (referred to asSNP_02) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:2 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);

and/or at least a Guanine (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO: 3 (referred to asSNP_03) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:3 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosine (CC) at nucleotide 75 of SEQ ID NO: 4 (referred to asSNP_04) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:4 (in other words there is aThymine at the physical position of chromosome 2 shown in Table 7);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosine (CC) at nucleotide 75 of SEQ ID NO: 5 (referred to asSNP_05) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:5 (in other words there is aThymine at the physical position of chromosome 2 shown in Table 7);and/or at least a Cytosine (C) (i.e. the CC or CT genotype) instead oftwo Thymine (TT) at nucleotide 75 of SEQ ID NO: 6 (referred to asSNP_06) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:6 (in other words there is aCytosine at the physical position of chromosome 2 shown in Table 7);and/or at least a Cytosine (C) (i.e. the CC or CT genotype) instead oftwo Thymine (TT) at nucleotide 75 of SEQ ID NO:7 (referred to as SNP_07)or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:7 (in other words there is aCytosine at the physical position of chromosome 2 shown in Table 7);and/or at least a Adenine (A) (i.e. the AA or AG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:8 (referred to asSNP_08) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:8 (in other words there is aAdenine at the physical position of chromosome 2 shown in Table 7);and/or at least a Thymine (T) (i.e. the TT or TG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:9 (referred to asSNP_09) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:9 (in other words there is aThymine at the physical position of chromosome 2 shown in Table 7);and/or at least a Thymine (T) (i.e. the TT or TG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:10 (referred to asSNP_10) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:10 (in other words there is aThymine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (TG (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:11 (referred to asSNP_11) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:11 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least an Guanine (G) (i.e. the GG or GT genotype) instead oftwo Thymines (TT) at nucleotide 75 of SEQ ID NO:12 (referred to asSNP_12) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:12 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Cytosine (C) (i.e. the CC or CA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:13 (referred to asSNP_13) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:13 (in other words there is aCytosine at the physical position of chromosome 2 shown in Table 7);and/or at least an Adenine (A) (i.e. the AA or AG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:14 (referred to asSNP_14) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:14 (in other words there is aAdenine at the physical position of chromosome 2 shown in Table 7);and/or at least a Cytosine (C) (i.e. the CC or CT genotype) instead oftwo Thymines (TT) at nucleotide 75 of SEQ ID NO: 15 (referred to asSNP_15) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:15 (in other words there is aCytosine at the physical position of chromosome 2 shown in Table 7);and/or at least a Adenine (A) (i.e. the AA or AC genotype) instead oftwo Cytosines (CC) at nucleotide 75 of SEQ ID NO: 16 (referred to asSNP_16) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:16 (in other words there is aAdenine at the physical position of chromosome 2 shown in Table 7);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosines (CC) at nucleotide 75 of SEQ ID NO: 17 (referred to asSNP_17) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:17 (in other words there is aThymine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO: 18 (referred to asSNP_18) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:18 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Adenine (A) (i.e. the AA or AG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:19 (referred to asSNP_19) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:19 (in other words there is aAdenine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:20 (referred to asSNP_20) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:20 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least an Guanine (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:21 (referred to asSNP_21) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:21 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (G) (i.e. the GG or GT genotype) instead oftwo Thymines (TT) at nucleotide 75 of SEQ ID NO:22 (referred to asSNP_22) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:22 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Thymine (T) (i.e. the TT or TG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:23 (referred to asSNP_23) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:23 (in other words there is aThymine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (G) (i.e. the GG or GT genotype) instead oftwo Thymines (TT) at nucleotide 75 of SEQ ID NO:24 (referred to asSNP_24) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:24 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Guanine (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:25 (referred to asSNP_25) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:25 (in other words there is aGuanine at the physical position of chromosome 2 shown in Table 7);and/or at least a Cytosine (C) (i.e. the CC or CA genotype) instead oftwo Adenines (AA) at nucleotide 251 of SEQ ID NO:26 (referred to asSNP_26) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:26 (in other words there is aCytosine at the physical position of chromosome 2 shown in Table 7).

In a further one embodiment the presence of the introgression fragment,or the chromosome 2 region (or variant or orthologous chromosome 2region), comprising QTL2.1, is detectable by a molecular marker assaywhich detects at least 1, preferably at least 2, 3, 4, 5, 6, 7, 8, ormore Single Nucleotide Polymorphism (SNP) markers of the sub-groupsconsisting of: SNP_01 to SNP_10 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_01 andSNP_10; SNP_10 to SNP_20 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_10 andSNP_20; SNP_20 to SNP_26 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_20 andSNP_26; or SNP_06 to SNP_23 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_06 andSNP_23.

The SNP genotype refers to two nucleotides, and genomic sequencescomprising one of these two nucleotides, one on each chromosome 2. So aplant having a CC genotype for SNP_01 has an identical nucleotide (C) onboth chromosomes (i.e. is homozygous for the introgression fragment),while a plant having an CT genotype for SNP_01 has one chromosome with aC at nucleotide 75 of SEQ ID NO: 1 (or at the equivalent nucleotide of agenomic sequence comprising substantial sequence identity to SEQ IDNO:1) and one chromosome with a T at nucleotide 75 of SEQ ID NO: 1 (orat the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:1) and is heterozygous forthe introgression fragment. As the genomic sequences around the SNPmarkers provided herein may vary slightly in introgression fragmentsfrom other wild relatives of cucumber (i.e. variants or orthologouschromosome 2 regions) it is clear that the nucleotide sequences beforeand after the SNP may not be 100% identical to the sequences providedherein. Therefore sequences having substantial sequence identity to thesequences provided herein (when aligned over the entire length asdefined), but which comprise the same SNP genotype, are encompassedherein.

In one aspect, the introgression fragment, or the chromosome 2 region(or variant or orthologous chromosome 2 region) comprising the QTL(QTL2.1 or variant), which is detectable by the above one or moremarkers is from a wild relative of cucumber, and in one aspect the wildrelative is a member of the Indian Cucumber Group. In one aspect it isthe same introgression fragment as found on chromosome 2 in seedsdeposited under accession number NCIMB42545, or a smaller fragmentretaining the QTL. SNP markers SNP_01 to SNP_26 span a region of about5.4 Mb. In one aspect the introgression fragment on chromosome 2 isequal to or less than 10 Mb in size, preferably equal to or less than 8Mb in size, more preferably equal to or less than 6 Mb, 5.5 Mb, 5.4 MB,5 Mb, 4 Mb, 3 Mb or 2.5 Mb in size, e.g. equal to or less than 2 Mb. Inone aspect the introgression fragment is at least 0.2 Mb, 0.5 Mb, 1.0Mb, 1.5 Mb, 1.9 Mb, 2.0 Mb, 2.5 Mb, 2.7 Mb or 3 Mb in size. Thus,various ranges of introgression fragment sizes are encompassed herein,such as fragments less than 10 Mb but more than 0.2 Mb, less than 6 Mbor 5.5 Mb but more than 0.2 Mb, 0.5 MB or 1 Mb, etc., which retain theQTL2.1 and one or more of the SNP markers of SNP_01 to SNP_26, or of thesubgroups of SNP_01 to SNP_10; SNP_10 to SNP_20; SNP_20 to SNP_26 orSNP_06 to SNP_23. As mentioned before, the location of the QTL2.1 in theregion spanning SNP_01 to SNP_26 can be determined by fine-mapping andrecombinants comprising QTL2.1 on a smaller introgression fragment canbe generated. The size of an introgression fragment can be easilydetermined by e.g. whole genome sequencing or Next GenerationSequencing, e.g. as described in Qi et al. 2013 (supra) or in Huang etal. 2009 (supra). Especially introgression regions can be easilydistinguished from cultivated genomic regions due to the larger amountof genetic variation (SNPs, INDELs, etc.) in the introgression region.

To obtain the introgression fragment present on chromosome 2 from thedeposited seeds (NCIMB42545), i.e. to transfer the introgressionfragment comprising the QTL to another cultivated cucumber plant, aplant is grown from the seed and the plant is crossed with a cultivatedcucumber plant to obtain F1 seeds. As NCIMB42545 contains tworecombinant chromosomes 2 (comprising the introgression fragmentcomprising QTL2.1 in homozygous form) all of the F1 seed and plantsgrown therefrom will contain one recombinant chromosome 2 from theNCIMB42545 parent and one non-recombinant chromosome 2 from the othercultivated parent. By further selfing and/or crossing and/orbackcrossing, QTL2.1 can be transferred into any cucumber breeding lineor variety. Thus, by traditional breeding one can transfer therecombinant chromosome 2 from NCIMB42545 into other cultivated cucumberlines or varieties. Progeny plants which comprise the QTL2.1 can bescreened for, and selected for, by the presence of one or more of theabove SNP markers.

To generate shorter introgression fragments, e.g. sub-fragments of thefragment present in NCIMB42545, meiosis needs to take place and plantscomprising the recombinant chromosomes 2, and especially new meioticrecombination events within the introgression fragment, need to beidentified. For example, seeds of NCIMB42545 can be selfed one or moretimes to produce F1, F2 or F3 plants (or further selfing generations),and/or F1, F2 or F3 plants (etc.) comprising the recombinant chromosome2 can be backcrossed to a cultivated parent. Plants which comprise therecombinant chromosome 2 can be screened for, and selected for, by thepresence of one or more of the above SNP markers in order to identifyplants comprising a smaller introgression fragment. Such newrecombinants can then be tested for the presence of the QTL2.1 on thesmaller introgression fragment by determining the average fruit yieldcompared to the (genetic) control lacking the introgression fragment.

Similarly, cultivated cucumber plants comprising QTL2.1 (or a variantthereof) can be generated and/or identified using different methods. Forexample, to obtain a cultivated cucumber plant comprising aintrogression fragment from a wild relative of cucumber, first a wildrelative of cucumber is identified which comprises one or more of theSNP markers linked to QTL2.1 disclosed herein, e.g. any one, or more, orall of the markers described herein above. The identified plant iscrossed with a cultivated cucumber plant to obtain F1 seeds. The the F1can be selfed to produce F2, F3, etc. plants, and/or F2 plants or F3plants, etc., can be backcrossed to the cultivated cucumber parent.Plants which are comprising QTL2.1 (or a variant thereof) can bescreened for, and/or selected for, by the presence of one or more of theabove SNP markers and/or screened for, and/or selected for, an increasedyield phenotype compared to the initial cultivated parent (lacking theintrogressions). Alternatively or in addition, QTL mapping or sequencingcan be carried out in order to identify further molecular markers linkedto the QTL2.1 (or a variant thereof) and/or to generate cultivatedcucumber plants comprising an introgression fragment on chromosome 2which confers significantly enhanced yield.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 2 region (or orthologouschromosome 2 region), comprising QTL2.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_01 in SEQ ID NO: 1 (or in a variant thereof);-   b) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_26 in SEQ ID NO: 26 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_01 and SNP_26;-   d) any wild-relative of cucumber genome-specific marker which is    genetically linked within 7 cM, 5 cM, 3 cM or less of marker SNP_01    or SNP_26; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_01 or SNP_26.

In one aspect the markers of c) are one or more of SNP_02 to SNP_25. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 2 region (or orthologouschromosome 2 region), comprising QTL2.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_01 in SEQ ID NO: 1 (or in a variant thereof);-   b) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_01 and SNP_10; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_01 or SNP_10; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_01 or SNP_10.

In one aspect the markers of c) are one or more of SNP_02 to SNP_09. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 2 region (or orthologouschromosome 2 region), comprising QTL2.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   b) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_10 and SNP_20; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_10 or SNP_20; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_10 or SNP_20.

In one aspect the markers of c) are one or more of SNP_11 to SNP_19. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 2 region (or orthologouschromosome 2 region), comprising QTL2.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   b) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_26 in SEQ ID NO: 26 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_20 and SNP_26; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_20 or SNP_26; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_20 or SNP_26.

In one aspect the markers of c) are one or more of SNP_21 to SNP_25. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 2 region (or orthologouschromosome 2 region), comprising QTL2.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_06 in SEQ ID NO: 06 (or in a variant thereof);-   b) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_23 in SEQ ID NO: 23 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_06 and SNP_23; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_06 or SNP_23; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_06 or SNP_23.

In one aspect the markers of c) are one or more of SNP_07 to SNP_22. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

Any wild-relative of cucumber genome-specific marker in between twomarkers refers to any molecular marker which maps genetically to thechromosome 2 region in-between the two markers and/or which liesphysically in-between the two markers, and which is indicative of thewild-relative of cucumber chromosome 2 region. This means that themarker is polymorphic between the cultivated cucumber genome and thewild-relative of cucumber genome. In one aspect, the marker is a SingleNucleotide Polymorphism (SNP), but other molecular markers such as RFLP,AFLP, RAPD, INDEL, DNA sequencing, etc. may equally be used.

The introgression fragment in the plants of the invention is in oneaspect a fragment of the chromosome 2 which is present in seedsdeposited under accession number NCIMB 42545 or a smaller version ofthat fragment retaining the QTL (generated by e.g. recombination withinthe introgression fragment).

The introgression fragment is in one aspect equal to or less than 10 Mbin size, preferably equal to or less than 8 Mb, 5.4 Mb, 5 Mb, 3 Mb, 2.5Mb, 2 Mb, 1.5 Mb, 1 Mb in size. In a further aspect the introgressionfragment is at least 0.5 Mb or at least 1 Mb in size.

Also provided are seeds from which a plant of the invention can begrown, as are cucumber fruits harvested from a plant of the inventionand comprising the recombinant chromosome 2 in their genome. Likewise aplant cell, tissue or plant part of a plant or of a seed is providedcomprising at least one recombinant chromosome 2, wherein saidrecombinant chromosome 2 comprises an introgression fragment from a wildrelative of cucumber and wherein said introgression fragment comprisesan allele conferring significantly enhanced fruit yield.

Cucumber Plants Comprising an Introgression Fragment on Chromosome 6(Yield TL 6.1)

QTL6.1 is located in the region between SNP_27 in SEQ ID NO: 27 (or in avariant thereof) and SNP_40 in SEQ ID NO: 40 (or a variant thereof).

Thus in one aspect a cultivated Cucumis sativus var. sativus plant isprovided comprising an introgression fragment on chromosome 6 inhomozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay (i.e. the plant comprises one or more molecular markers) whichdetects at least 1, preferably at least 2 or 3, or at least 4, 5, 6, 7,8, 9, 10, 11, 12, 13 or 14 of the markers selected from the groupconsisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_27 in SEQ ID NO: 27 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_28 in SEQ ID NO: 28 (or in a variant thereof);-   c) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_29 in SEQ ID NO: 29 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_30 in SEQ ID NO: 30 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_31 in SEQ ID NO: 31 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_32 in SEQ ID NO: 32 (or in a variant thereof);-   g) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   h) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_34 in SEQ ID NO: 34 (or in a variant thereof);-   i) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_35 in SEQ ID NO: 35 (or in a variant thereof);-   j) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_36 in SEQ ID NO: 36 (or in a variant thereof);-   k) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_37 in SEQ ID NO: 37 (or in a variant thereof);-   l) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_38 in SEQ ID NO: 38 (or in a variant thereof);-   m) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_39 in SEQ ID NO: 39 (or in a variant thereof);-   n) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_40 in SEQ ID NO: 40 (or in a variant thereof).-   o) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_40.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 markers are selected from thegroup consisting of markers a) to n). In one aspect said at least 1,preferably at least 2 or 3, or at least 4, 5, 6, 7, 8, 9, 10, 11, 12, 13or 14 markers are consecutive markers.

In another aspect QTL6.1 is located in the region between SNP_27 in SEQID NO: 27 (or in a variant thereof) and SNP_33 in SEQ ID NO: 33 (or avariant thereof).

Thus in one aspect a cultivated Cucumis sativus var. sativus plant isprovided comprising an introgression fragment on chromosome 6 inhomozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay (i.e. the plant comprises one or more molecular markers) whichdetects at least 1, preferably at least 2 or 3, or at least 4, 5, 6 or 7of the markers selected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_27 in SEQ ID NO: 27 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_28 in SEQ ID NO: 28 (or in a variant thereof);-   c) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_29 in SEQ ID NO: 29 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_30 in SEQ ID NO: 30 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_31 in SEQ ID NO: 31 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_32 in SEQ ID NO: 32 (or in a variant thereof);-   g) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   h) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_33.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, or 7 markers are selected from the group consisting of markersa) to g). In one aspect said at least 1, preferably at least 2 or 3, orat least 4, 5, 6, or 7 markers are consecutive markers.

In a different aspect QTL6.1 is located in the region between SNP_33 inSEQ ID NO: 33 (or in a variant thereof) and SNP_40 in SEQ ID NO: 40 (ora variant thereof).

Thus in one aspect a cultivated Cucumis sativus var. sativus plant isprovided comprising an introgression fragment on chromosome 6 inhomozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay (i.e. the plant comprises one or more molecular markers) whichdetects at least 1, preferably at least 2 or 3, or at least 4, 5, 6, 7or 8 of the markers selected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_34 in SEQ ID NO: 34 (or in a variant thereof);-   c) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_35 in SEQ ID NO: 35 (or in a variant thereof);-   d) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_36 in SEQ ID NO: 36 (or in a variant thereof);-   e) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_37 in SEQ ID NO: 37 (or in a variant thereof);-   f) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_38 in SEQ ID NO: 38 (or in a variant thereof);-   g) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_39 in SEQ ID NO: 39 (or in a variant thereof);-   h) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_40 in SEQ ID NO: 40 (or in a variant thereof).-   i) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_40.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7 or 8 markers are selected from the group consisting ofmarkers a) to h). In one aspect said at least 1, preferably at least 2or 3, or at least 4, 5, 6, 7 or 8 markers are consecutive markers.

In another embodiment QTL6.1 is located in the region between SNP_29 inSEQ ID NO: 29 (or in a variant thereof) and SNP_38 in SEQ ID NO: 38 (ora variant thereof).

Thus in one aspect a cultivated Cucumis sativus var. sativus plant isprovided comprising an introgression fragment on chromosome 6 inhomozygous or heterozygous form, wherein said introgression fragmentconfers an increase in cucumber fruit yield (compared to the plantlacking the introgression fragment, e.g. the genetic control) andwherein said introgression fragment is detectable by a molecular markerassay (i.e. the plant comprises one or more molecular markers) whichdetects at least 1, preferably at least 2 or 3, or at least 4, 5, 6, 7,8 or 9 of the markers selected from the group consisting of:

-   a) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_29 in SEQ ID NO: 29 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_30 in SEQ ID NO: 30 (or in a variant thereof);-   c) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_31 in SEQ ID NO: 31 (or in a variant thereof);-   d) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_32 in SEQ ID NO: 32 (or in a variant thereof);-   e) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   f) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_34 in SEQ ID NO: 34 (or in a variant thereof);-   g) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_35 in SEQ ID NO: 35 (or in a variant thereof);-   h) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_36 in SEQ ID NO: 36 (or in a variant thereof);-   i) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_37 in SEQ ID NO: 37 (or in a variant thereof);-   j) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_38 in SEQ ID NO: 38 (or in a variant thereof);-   k) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_40.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8 or 9 markers are selected from the group consisting ofmarkers a) to j). In one aspect said at least 1, preferably at least 2or 3, or at least 4, 5, 6, 7, 8 or 9 markers are consecutive markers.

As QTL6.1 especially enhances fruit yield in cold growing conditions, itis especially advantageous for cucumber plant lines and varieties whichmay be grown under environmental conditions where the minimumtemperatures are low, e.g. 10 degrees Celsius or less (such as equal toor less than 9, 8, 7, 6, 5 or 4 degrees Celsius), for a certain periodof time (but freezing should be avoided, as this causes freezingdamage). Thus in one aspect the fruit yield of the cultivated cucumberplant of the invention, comprising QTL6.1, is increased compared to thecontrol when the plant is grown under environmental conditions where theminimum temperature (e.g. at night) is equal to or below 10 degreesCelsius, such as autumn/winter periods in southern European countries orspring periods in northern European countries.

As mentioned, the skilled person can also develop other molecularmarkers, e.g. a wild-relative of cucumber genome-specific markerin-between marker SNP_27 and SNP_40 and/or within 7 cM or within 5 cM ofany one of SNP_27 to SNP_40, and/or within 5 Mb, 3 Mb, 2.5 Mb, 2 Mb, 1Mb, 0.5 Mb, 0.4 Mb, 0.3 Mb, 0.2 Mb, 0.1 Mb, 50 kb, 20 kb, 10 kb, 5 kb orless of any one of SNP_27 to SNP_40. Such markers may also be a stretchof nucleotide, CAPS markers, INDELs, etc. The skilled person can, forexample, sequence the introgression fragment found in seeds depositedunder accession number NCIMB42545 and use the sequence information todevelop new markers and marker assays.

The introgression fragment comprising the QTL6.1 (or a variant) maycomprise all SNP markers disclosed herein, or it may be smaller and lackSNP markers indicative of the introgression fragment (having the SNPgenotype of cultivated cucumber instead), while it still confersenhanced yield on the cultivated cucumber plant, i.e. it can stillcomprise the yield allele (QTL6.1 or variant). Such smallerintrogression fragments are an embodiment of the invention. Plantshaving smaller introgression fragments which still confer the enhancedyield (i.e. contain the yield allele) can be generated using knowntechniques, such as fine-mapping or similar techniques. For example bystarting with a plant comprising the introgression fragment as found inseeds deposited under accession number NCIMB 42545 and crossing such aplant with another cultivated cucumber plant and selfing the progeny ofsaid cross, and/or backcrossing the progeny, to generate a population ofplants which may contain recombinants having a smaller introgressionfragment on chromosome 6, which fragments still confer enhanced yield inrelation to a plant lacking the introgression fragment (such as thegenetic control, e.g. plants grown from seeds deposited underNCIMB42345), e.g. a fragment comprising the wild relative genotype ofmarkers SNP_27 to SNP_33 (or smaller, e.g. comprising only 6, 5, 4, 3, 2or 1 of the SNP markers), SNP_33 to SNP_40 (or smaller e.g. comprisingonly 6, 5, 4, 3, 2 or 1 of the SNP markers), SNP_29 to SNP_38 (orsmaller e.g. comprising only 9, 8, 7, 6, 5, 4, 3, 2 or 1 of the SNPmarkers). Marker assays can be used to select recombinants and todetermine the size of the smaller introgression fragment. One or more ofSNP markers may be missing. The yield of plants comprising such asmaller introgression fragment can then be compared in yield experimentsas described herein, i.e. growing a plurality of plants comprising thesmaller introgression fragment in field experiments together withsuitable control plants, lacking the introgression fragment. The controlplants are preferably a genetic control, such as NCIMB42345. If theaverage yield remains significantly higher than in the control, then thesmaller introgression fragment has retained the QTL6.1.

Alternatively, the same or variant QTL (QTL6.1 or variant QTL6.1) may beintrogressed from a different wild relative of cucumber, wherebyoptionally not all SNP markers disclosed herein are present. Suchalternative wild relative of cucumber sources can be identified usingthe SNP markers provided herein, by screening germplasm (i.e. accessionsof) wild relatives of cucumber using a marker assay to detect thegenotype of markers SNP_27 to SNP_40, or of markers SNP_27 to SNP_33,SNP_33 to SNP_40, SNP_29 to SNP_38, or even only a smaller subgroup ofthese markers (e.g. 2, 3, 4, 5, 6 or more). Plants comprising the sameor variant QTL6.1 from other sources are also an embodiment of theinvention. As long as at least one or more (or all) of the SNPs ofSNP_27 to SNP_40, or of the SNPs of SNP_27 to SNP_33, or of the SNPs ofSNP_33 to SNP_40, or of the SNPs of SNP_29 to SNP_38 is present, and theplant has the yield-increasing genotype, i.e. the plant comprises QTL6.1(or a variant thereof). The skilled person can then introgress theQTL6.1 (or a variant thereof) into cultivated cucumber in order toenhance fruit yield as described herein and in order to confirm that theQTL enhances yield when present in cultivated cucumber. For example,QTL6.1 can be introgressed into a specific breeding line or variety andthe line or variety without the introgression can be used as the geneticcontrol in yield trials.

As described above, in one embodiment the cultivated cucumber plant ofthe invention comprises an introgression fragment comprising at least asubset of SNP markers with the genotype of the wild relative ofcucumber, i.e. at least 1, 2, 3, 4, or 5 markers of SNP_27 to SNP_40, orof SNP_27 to SNP_33, or of SNP_33 to SNP_40, or of SNP_29 to SNP_38. Inone aspect the cultivated cucumber plant comprises all, or all except 1or 2 markers of SNP_27 to SNP_40, or of SNP_27 to SNP_33, or of SNP_33to SNP_40, or of SNP_29 to SNP_38.

Thus, the introgression fragment (and a cultivated cucumber plant orplant part, e.g., a cell, comprising the introgression fragment) can bedetected in a marker assay by detecting the SNP genotype of theintrogression fragment (i.e. of the wild relative of cucumber germplasm)of one or more or all of the markers above.

Thus, in one aspect, a Quantitative Trait Locus (QTL6.1) was found to bepresent on chromosome 6 of a wild relative of cucumber which, whentransferred (introgressed) into a cultivated cucumber variety orbreeding line, and when present in heterozygous or homozygous form,confers significantly enhanced fruit yield onto the cultivated cucumberplant. The QTL, or the introgression fragment comprising the QTL(comprising the yield allele), is thus dominant, i.e. it is sufficientto have the introgression fragment on one of the chromosomes 6 (onerecombinant chromosome 6), while the homologous chromosome 6 of the pairmay be a (non-recombinant) chromosome 6 of cultivated C. sativus var.sativus lacking the introgression fragment.

Although the present source of the yield QTL is a single, specific wildsource, there are likely other wild relatives of Cucumis accessionswhich comprise QTL6.1 at the same locus on chromosome 6. Such loci maycomprise yield alleles which have slightly different nucleotidesequences, i.e. variants of the allele (QTL) found herein. Such variantQTLs can also be identified and introgressed into cultivated cucumber asdescribed herein, to generate a cultivated cucumber plant comprising agenome of cultivated C. sativus var. sativus and a recombinantchromosome 6, whereby the recombinant chromosome 6 comprises a wildrelative of Cucumis sativus species introgression fragment, whichconfers an enhanced yield phenotype onto the cultivated cucumber plantwhen present in homozygous or heterozygous form. To identify such wildrelatives of cucumber comprising QTL6.1, wild accessions can bescreened, e.g. in a marker assay or by sequence comparison or othermethods, for the presence of one or more of the SNP markers providedherein. The putative yield QTLs (or variant QTLs) can then beintrogressed into cultivated cucumber, e.g. using MAS, i.e. using one ormore (or all) of the SNP markers provided herein to detect and/or selectprogeny plants (e.g. backcross plants) comprising a recombinantchromosome 6. The selected plants, i.e. the cultivated cucumber plantscomprising an introgression fragment on chromosome 6, wherein theintrogression fragment on chromosome 6 is detectable by one or more ofthe SNP markers SNP_27 to SNP_40, or of SNP_27 to SNP_33, or of SNP_33to SNP_40, or of SNP_29 to SNP_38 (as described elsewhere herein) canthen be phenotyped in yield experiments together with the suitablecontrol plants, preferably at least the genetic control, in order todetermine whether the introgression fragment indeed causes a significantyield increase.

Accessions of wild relatives of cucumber, are obtainable from the USDANational Plant Germplasm System collection or other seed collections,and can thus be screened for the presence of QTL6.1 using e.g. a markerassay as described herein, and accessions comprising one or more of theSNP markers (e.g. at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13 orall 14 SNP markers indicative of QTL6.1 can be crossed with a cultivatedcucumber plant having normal wild-type, non-recombinant chromosomes 6.The F1 or F2 generation (or further generation, such as the F3 or abackcross generation) can then be screened for recombinant plants havingthe introgression fragment, or a yield increasing part thereof, usingthe molecular marker assays described herein.

In one aspect, the introgression fragment is from a wild relative ofcucumber, which belongs to the Indian Cucumber Group, and which istransferred onto chromosome 6 of the Eurasian Cucumber Group, therebycreating a cultivated cucumber plant comprising yield QTL6.1 or avariant thereof. Thus, in one embodiment the introgression fragmentcomprising the yield QTL6.1 is derivable from (or derived from) orobtainable from (or obtained from; or as present in) a wild relative ofcucumber which belongs to the Indian Cucumber Group.

In a specific embodiment, the introgression fragment comprising theyield QTL6.1 is derivable from (or derived from) or obtainable from (orobtained from; or as present in) seeds, a representative sample of whichhas been deposited under accession number NCIMB 42545, or from progenythereof. The progeny may be any progeny which retain the one or more (orall) SNP markers indicative of (and linked to) the QTL, as described.Thus, progeny are not limited to F1 or F2 progeny of the deposit, butcan be any progeny, whether obtained by selfing and/or crossing withanother cucumber plant.

In one embodiment the introgression fragment is identifiable by one ormore of the markers described elsewhere herein, especially markersSNP_27 to SNP_40 for the introgression fragment on chromosome 6, or asubset of markers, such as one or more of the markers selected from SNPmarkers SNP_27 to SNP_33, or of SNP_33 to SNP_40, or of SNP_29 toSNP_38. In one aspect the invention provides a cultivated cucumberplant, having a genome of cultivated (domesticated) cucumber whichcomprises enhanced fruit yield, wherein the enhanced fruit yield isconferred by an introgression fragment on the cultivated cucumberchromosome 6, wherein said introgression fragment is obtained by (orobtainable by) crossing a cultivated plant grown from seeds depositedunder NCIMB 42545 or progeny of this plant (which comprises one or morethe markers disclosed herein linked to the QTL) with a cultivatedcucumber plant. Thus in one aspect the cultivated cucumber plant of theinvention comprises the same introgression fragment and the samerecombinant chromosome 6 as present in NCIMB 42545 (comprising the wildrelative of cucumber genotype for SNP_27 to SNP_40), or it comprises ashorter fragment of that introgression fragment, whereby the shorterfragment retains the genetic element conferring enhanced fruit yield(QTL6.1).

Thus in one aspect the invention relates to a plant of the inventioni.e. a cultivated Cucumis sativus var. sativus plant comprising anintrogression fragment from a wild relative of cucumber on chromosome 6in homozygous or heterozygous form and wherein said introgressionfragment is the introgression fragment “as in”/is “identical to”/is “thesame as in” the seeds deposited under number NCIMB 42545, or is ashorter fragment thereof, but still confers enhanced fruit yield due tothe presence of QTL6.1.

In yet another embodiment the invention relates to a plant of theinvention i.e. a cultivated Cucumis sativus var. sativus plantcomprising an introgression fragment from a wild relative of cucumber onchromosome 6, in homozygous or heterozygous form, and wherein saidintrogression fragment is a variant of the introgression fragment foundin seeds deposited under number NCIMB 42545, i.e. it comprises the yieldQTL 6.1, but the genomic sequence may be different. As wild accessionswill be genetically divergent, the genomic sequence of an introgressionfragment comprising QTL6.1 from other wild relatives of cucumber willmost likely not be identical to the genomic sequence as introgressedinto NCIMB42545, and even the yield conferring gene (comprising apromoter, introns and exons) may be divergent in nucleotide sequence,but the function will be the same, i.e. conferring enhanced fruit yield.The divergence can be seen in that certain SNP markers linked to QTL6.1may be commonly found in various accessions, while other SNP markers mayonly be found in specific accessions. So for example not all of SNP_27to SNP_40 may be found in other wild relatives of cucumber. However, theyield enhancing QTL6.1 (comprising e.g. a variant or ortholog of theyield allele) may still be present in such wild accessions. The skilledperson is capable of identifying and introgressing the QTLs 6.1comprising region found in other wild relatives of cucumber intocultivated cucumber, e.g. detecting wild relatives comprising the SNPmarkers or a subset thereof and transferring these SNP markers (orsubset) into a cultivated cucumber line or variety and assessing thefruit yield of the cultivated line or variety compared to the line orvariety lacking the SNP markers (or subset), i.e. lacking theintrogression fragment.

In one embodiment the presence of the introgression fragment, or thechromosome 6 region (or variant or orthologous chromosome 6 region),comprising QTL6.1, is detectable by a molecular marker assay whichdetects at least 1, preferably at least 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,12, 13 or more (or all 14) Single Nucleotide Polymorphism (SNP) markersselected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_27 in SEQ ID NO: 27 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_28 in SEQ ID NO: 28 (or in a variant thereof);-   c) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_29 in SEQ ID NO: 29 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_30 in SEQ ID NO: 30 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_31 in SEQ ID NO: 31 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_32 in SEQ ID NO: 32 (or in a variant thereof);-   g) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   h) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_34 in SEQ ID NO: 34 (or in a variant thereof);-   i) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_35 in SEQ ID NO: 35 (or in a variant thereof);-   j) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_36 in SEQ ID NO: 36 (or in a variant thereof);-   k) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_37 in SEQ ID NO: 37 (or in a variant thereof);-   l) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_38 in SEQ ID NO: 38 (or in a variant thereof);-   m) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_39 in SEQ ID NO: 39 (or in a variant thereof);-   n) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_40 in SEQ ID NO: 40 (or in a variant thereof).-   o) optionally any wild relative of cucumber genome-specific marker    in between marker SNP_27 and SNP_40.

In one aspect said at least 1, preferably at least 2 or 3, or at least4, 5, 6, 7, 8, 9, 10, 11, 12, 13 or 14 markers which are detected areconsecutive markers.

Thus, in one embodiment the plants according to the invention compriseat least a Guanine (G) (i.e. the GG or GA genotype) instead of twoAdenines (AA) at nucleotide 75 of SEQ ID NO: 27 (referred to as SNP_27)or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:27 (in other words there is aGuanine at the physical position of chromosome 6 shown in Table 8);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosines (CC) at nucleotide 75 of SEQ ID NO: 28 (referred to asSNP_28) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:28 (in other words there is aThymine at the physical position of chromosome 6 shown in Table 8);

and/or at least a Cytosine (C) (i.e. the CC or CA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO: 29 (referred to asSNP_29) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:29 (in other words there is aCytosine at the physical position of chromosome 6 shown in Table 8);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosine (CC) at nucleotide 75 of SEQ ID NO: 30 (referred to asSNP_30) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:30 (in other words there is aThymine at the physical position of chromosome 6 shown in Table 8);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosine (CC) at nucleotide 75 of SEQ ID NO: 31 (referred to asSNP_31) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:31 (in other words there is aThymine at the physical position of chromosome 6 shown in Table 8);and/or at least a Cytosine (C) (i.e. the CC or CT genotype) instead oftwo Thymine (TT) at nucleotide 75 of SEQ ID NO: 32 (referred to asSNP_32) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:32 (in other words there is aCytosine at the physical position of chromosome 6 shown in Table 8);and/or at least a Guanines (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:33 (referred to asSNP_33) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:33 (in other words there is aGuanine at the physical position of chromosome 6 shown in Table 8);and/or at least a Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosine (CC) at nucleotide 75 of SEQ ID NO:34 (referred to asSNP_34) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:34 (in other words there is aThyminee at the physical position of chromosome 6 shown in Table 8);and/or at least a Guanines (G) (i.e. the GG or GA genotype) instead oftwo Adenines (AA) at nucleotide 75 of SEQ ID NO:35 (referred to asSNP_35) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:35 (in other words there is aGuanine at the physical position of chromosome 6 shown in Table 8);and/or at least a Adenine (A) (i.e. the AA or AC genotype) instead oftwo Cytosines (CC) at nucleotide 75 of SEQ ID NO:36 (referred to asSNP_36) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:36 (in other words there is aAdenine at the physical position of chromosome 6 shown in Table 8);and/or at least a Adenine (A) (i.e. the AA or AG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:37 (referred to asSNP_37) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:37 (in other words there is aAdenine at the physical position of chromosome 6 shown in Table 8);and/or at least an Adenine (A) (i.e. the AA or AG genotype) instead oftwo Guanines (GG) at nucleotide 75 of SEQ ID NO:38 (referred to asSNP_38) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:38 (in other words there is aAdenine at the physical position of chromosome 6 shown in Table 8);and/or at least a Adenine (A) (i.e. the AA or AC genotype) instead oftwo Cytosines (CC) at nucleotide 75 of SEQ ID NO:39 (referred to asSNP_39) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:39 (in other words there is aAdenine at the physical position of chromosome 6 shown in Table 8);and/or at least an Thymine (T) (i.e. the TT or TC genotype) instead oftwo Cytosines (CC) at nucleotide 75 of SEQ ID NO:40 (referred to asSNP_40) or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:40 (in other words there is aThymine at the physical position of chromosome 6 shown in Table 8).

In a further one embodiment the presence of the introgression fragment,or the chromosome 6 region (or variant or orthologous chromosome 6region), comprising QTL6.1, is detectable by a molecular marker assaywhich detects at least 1, preferably at least 2, 3, 4, 5, 6 or moreSingle Nucleotide Polymorphism (SNP) markers of the sub-groupsconsisting of: SNP_27 to SNP_33 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_27 andSNP_33; SNP_33 to SNP_40 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_33 andSNP_40; SNP_29 to SNP_38 or any wild relative of cucumbergenome-specific marker physically located in between marker SNP_29 andSNP_38.

The SNP genotype refers to two nucleotides, and genomic sequencescomprising one of these two nucleotides, one on each chromosome 6. So aplant having a GG genotype for SNP_27 has an identical nucleotide (G) onboth chromosomes (i.e. is homozygous for the introgression fragment),while a plant having an GA genotype for SNP_27 has one chromosome with aG at nucleotide 75 of SEQ ID NO: 27 (or at the equivalent nucleotide ofa genomic sequence comprising substantial sequence identity to SEQ IDNO:27) and one chromosome with an A at nucleotide 75 of SEQ ID NO: 27(or at the equivalent nucleotide of a genomic sequence comprisingsubstantial sequence identity to SEQ ID NO:27) and is heterozygous forthe introgression fragment. As the genomic sequences around the SNPmarkers provided herein may vary slightly in introgression fragmentsfrom other wild relatives of cucumber (i.e. variants or orthologouschromosome 6 regions) it is clear that the nucleotide sequences beforeand after the SNP may not be 100% identical to the sequences providedherein. Therefore sequences having substantial sequence identity to thesequences provided herein (when aligned over the entire length asdefined), but which comprise the same SNP genotype, are encompassedherein.

In one aspect, the introgression fragment, or the chromosome 6 region(or variant or orthologous chromosome 6 region) comprising the QTL(QTL6.1 or variant), which is detectable by the above one or moremarkers is from a wild relative of cucumber, and in one aspect the wildrelative is a member of the Indian Cucumber Group. In one aspect it isthe same introgression fragment as found on chromosome 6 in seedsdeposited under accession number NCIMB42545, or a smaller fragmentretaining the QTL. SNP markers SNP_27 to SNP_40 span a region of about2.8 Mb. In one aspect the introgression fragment on chromosome 6 isequal to or less than 10 Mb in size, preferably equal to or less than 8Mb in size, more preferably equal to or less than 6 Mb, 5.5 Mb, 5.4 MB,5 Mb, 4 Mb, 3 Mb or 2.8 Mb in size, e.g. equal to or less than 2 Mb. Inone aspect the introgression fragment is at least 0.2 Mb, 0.5 Mb, 1.0Mb, 1.5 Mb, 1.9 Mb, 2.0 Mb, 2.5 Mb, 2.7 Mb, 2.8 Mb or 3 Mb in size.Thus, various ranges of introgression fragment sizes are encompassedherein, such as fragments less than 10 Mb but more than 0.2 Mb, lessthan 6 Mb or 5.5 Mb or 3 Mb, but more than 0.2 Mb, 0.5 MB or 1 Mb, etc.,which retain the QTL6.1 and one or more of the SNP markers of SNP_27 toSNP_40, or of the subgroups of SNP_27 to SNP_33; SNP_33 to SNP_40; orSNP_28 to SNP_38. As mentioned before, the location of the QTL6.1 in theregion spanning SNP_27 to SNP_40 can be determined by fine-mapping andrecombinants comprising QTL6.1 on a smaller introgression fragment canbe generated. The size of an introgression fragment can be easilydetermined by e.g. whole genome sequencing or Next GenerationSequencing, e.g. as described in Qi et al. 2013 (supra) or in Huang etal. 2009 (supra). Especially introgression regions can be easilydistinguished from cultivated genomic regions due to the larger amountof genetic variation (SNPs, INDELs, etc.) in the introgression region.

To obtain the introgression fragment present on chromosome 6 from thedeposited seeds (NCIMB42545), i.e. to transfer the introgressionfragment comprising the QTL to another cultivated cucumber plant, aplant is grown from the seed and the plant is crossed with a cultivatedcucumber plant to obtain F1 seeds. As NCIMB42545 contains tworecombinant chromosomes 6 (comprising the introgression fragmentcomprising QTL6.1 in homozygous form) all of the F1 seed and plantsgrown therefrom will contain one recombinant chromosome 6 from theNCIMB42545 parent and one non-recombinant chromosome 6 from the othercultivated parent. By further selfing and/or crossing and/orbackcrossing, QTL6.1 can be transferred into any cucumber breeding lineor variety. Thus, by traditional breeding one can transfer therecombinant chromosome 6 from NCIMB42545 into other cultivated cucumberlines or varieties. Progeny plants which comprise the QTL6.1 can bescreened for, and selected for, by the presence of one or more of theabove SNP markers.

To generate shorter introgression fragments, e.g. sub-fragments of thefragment present in NCIMB42545, meiosis needs to take place and plantscomprising the recombinant chromosomes 6, and especially new meioticrecombination events within the introgression fragment, need to beidentified. For example, seeds of NCIMB42545 can be selfed one or moretimes to produce F1, F2 or F3 plants (or further selfing generations),and/or F1, F2 or F3 plants (etc.) comprising the recombinant chromosome6 can be backcrossed to a cultivated parent. Plants which comprise therecombinant chromosome 6 can be screened for, and selected for, by thepresence of one or more of the above SNP markers in order to identifyplants comprising a smaller introgression fragment. Such newrecombinants can then be tested for the presence of the QTL6.1 on thesmaller introgression fragment by determining the average fruit yieldcompared to the (genetic) control lacking the introgression fragment.

Similarly, cultivated cucumber plants comprising QTL6.1 (or a variantthereof) can be generated and/or identified using different methods. Forexample, to obtain a cultivated cucumber plant comprising aintrogression fragment from a wild relative of cucumber, first a wildrelative of cucumber is identified which comprises one or more of theSNP markers linked to QTL6.1 disclosed herein, e.g. any one, or more, orall of the markers described herein above. The identified plant iscrossed with a cultivated cucumber plant to obtain F1 seeds. The the F1can be selfed to produce F2, F3, etc. plants, and/or F2 plants or F3plants, etc., can be backcrossed to the cultivated cucumber parent.Plants which are comprising QTL6.1 (or a variant thereof) can bescreened for, and/or selected for, by the presence of one or more of theabove SNP markers and/or screened for, and/or selected for, an increasedyield phenotype compared to the initial cultivated parent (lacking theintrogressions). Alternatively or in addition, QTL mapping or sequencingcan be carried out in order to identify further molecular markers linkedto the QTL6.1 (or a variant thereof) and/or to generate cultivatedcucumber plants comprising an introgression fragment on chromosome 6which confers significantly enhanced yield.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 6 region (or orthologouschromosome 6 region), comprising QTL6.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_27 in SEQ ID NO: 27 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_40 in SEQ ID NO: 40 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_40; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_27 or SNP_40; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_27 or SNP_40.

In one aspect the markers of c) are one or more of SNP_28 to SNP_39. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 6 region (or orthologouschromosome 6 region), comprising QTL6.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_27 in SEQ ID NO: 27 (or in a variant thereof);-   b) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_33; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_27 or SNP_33; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_27 or SNP_33.

In one aspect the markers of c) are one or more of SNP_28 to SNP_32. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 6 region (or orthologouschromosome 6 region), comprising QTL6.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_40 in SEQ ID NO: 40 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_33 and SNP_40; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_33 or SNP_40; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_33 or SNP_40.

In one aspect the markers of c) are one or more of SNP_34 to SNP_39. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

In one embodiment the presence of the introgression fragment in acultivated cucumber plant, or the chromosome 6 region (or orthologouschromosome 6 region), comprising QTL6.1, is detectable by a molecularmarker assay which detects at least one, two, three, four, five or moreof the markers selected from the group consisting of:

-   a) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_29 in SEQ ID NO: 29 (or in a variant thereof);-   b) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_38 in SEQ ID NO: 38 (or in a variant thereof);-   c) any wild relative of cucumber genome-specific marker in between    marker SNP_29 and SNP_38; d) any wild-relative of cucumber    genome-specific marker which is genetically linked within 7 cM, 5    cM, 3 cM or less of marker SNP_29 or SNP_38; and-   e) any wild-relative of cucumber genome-specific marker which is    physically linked within 5 Mb, 3 Mb, 2 Mb, 1 Mb, 0.5 Mb or 0.2 Mb or    less of marker SNP_29 or SNP_38.

In one aspect the markers of c) are one or more of SNP_30 to SNP_37. Inone aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b) and/or c) above. Inanother aspect, at least one, two, at least three, at least four or moremarkers are detected from the markers of a), b), c), d) and/or e) above.In one embodiment at least the marker of a) and/or b) is detected andoptionally at least one, two, three or more markers of c), d) and/or e)are detected. In one aspect the markers detected are consecutivemarkers.

Any wild-relative of cucumber genome-specific marker in between twomarkers refers to any molecular marker which maps genetically to thechromosome 6 region in-between the two markers and/or which liesphysically in-between the two markers, and which is indicative of thewild-relative of cucumber chromosome 6 region. This means that themarker is polymorphic between the cultivated cucumber genome and thewild-relative of cucumber genome. In one aspect, the marker is a SingleNucleotide Polymorphism (SNP), but other molecular markers such as RFLP,AFLP, RAPD, INDEL, DNA sequencing, etc. may equally be used.

The introgression fragment in the plants of the invention is in oneaspect a fragment of the chromosome 6 which is present in seedsdeposited under accession number NCIMB 42545 or a smaller version ofthat fragment retaining the QTL (generated by e.g. recombination withinthe introgression fragment).

The introgression fragment is in one aspect equal to or less than 10 Mbin size, preferably equal to or less than 8 Mb, 5.4 Mb, 5 Mb, 3 Mb, 2.8Mb, 2.5 Mb, 2 Mb, 1.5 Mb, 1 Mb in size. In a further aspect theintrogression fragment is at least 0.5 Mb or at least 1 Mb in size.

Also provided are seeds from which a plant of the invention can begrown, as are cucumber fruits harvested from a plant of the inventionand comprising the recombinant chromosome 6 in their genome. Likewise aplant cell, tissue or plant part of a plant or of a seed is providedcomprising at least one recombinant chromosome 6, wherein saidrecombinant chromosome 6 comprises an introgression fragment from a wildrelative of cucumber and wherein said introgression fragment comprisesan allele conferring significantly enhanced fruit yield.

As mentioned previously, it is also an aspect to combine both QTL2.1 andQTL6.1 in a single cultivated cucumber plant. All embodiments relatingto the individual QTLs herein are therefore also combined in one aspectof the invention. As QTL6.1 especially enhances yield in cold growingconditions, the combination is especially advantageous for varietieswhich may be grown under environmental conditions where the minimumtemperatures are low, e.g. 10 degrees Celsius or less (such as equal toor less than 9, 8, 7, 6, 5 or 4 degrees Celsius), for a certain periodof time (but freezing should be avoided, as this causes freezingdamage).

The molecular markers described herein may be detected according tostandard method. For example SNP markers can easily be detected using aKASP-assay (see www.kpbioscience.co.uk) or other SNP genotyping assays.For developing a KASP-assay, for example 70 base pairs upstream and 70base pairs downstream of the SNP can be selected and two allele-specificforward primers and one allele specific reverse primer can be designed.See e.g. Allen et al. 2011, Plant Biotechnology J. 9, 1086-1099,especially p 097-1098 for KASP assay method.

Thus, in one aspect, the SNP markers and the presence/absence of themarker associated with the yield QTLs is determined using a KASP assay,but equally other SNP genotyping assays can be used. For example, aTaqMan SNP genotyping assay, a High Resolution Melting (HRM) assay,SNP-genotyping arrays (e.g. Fluidigm, Illumina, etc.) or DNA sequencingmay equally be used.

The physical size of an introgression fragment can be determined byvarious methods, such as physical mapping, sequencing or byvisualization of the introgression using Fluorescent in situhybridization (FISH) images (Verlaan et al. 2011, Plant Journal 68:1093-1103).

Cultivated cucumber plants with smaller introgression fragments onchromosome 2 and/or 6 can be generated by generating new recombinantplants from a population of plants derived from a cross between acultivated cucumber plant (lacking the introgressions) and a plant ofthe invention and selecting recombinant progeny having smallerintrogression sizes. Such plants are, thus, in one aspect derived from(progeny or descendants of) the recombinant chromosome 2 and 6 presentin plants of which seeds have been deposited under NCIMB42545. Suchprogeny or descendants which retain the QTL2.1 and/or QTL6.1, and thusthe higher yield compared to plants lacking the introgression(s) asdescribed herein, are encompassed herein.

In tomato, for example the large S. chilense introgression fragment onchromosome 6 (about 27 cM) which comprises the Ty-3 allele has beenreduced by selecting a recombinant progeny line (LA1931-AL-F2), whichcomprises a much smaller S. chilense introgression fragment (about 6 cM)comprising Ty-3 (see Ji et al. 2007, Mol. Breeding 20: 271-284).

The cultivated cucumber plant according to the invention may be aninbred line, an OP (open pollinated variety) or an F1 hybrid. In oneaspect the F1 hybrid comprises only one recombinant chromosome 2 and/orone recombinant chromosome 6 (comprising the introgression fragment withthe QTL), i.e. the F1 hybrid is heterozygous for the introgressionfragment(s) and the SNP markers described herein. Such an F1 hybrid isproduced by crossing two inbred parent lines, one of which possesses theintrogression fragment(s) (preferably in homozygous form, although notnecessarily) and collecting the F1 hybrid seeds from said cross. Inanother aspect the F1 hybrid may comprise the introgression fragment(s)in homozygous form, i.e. produced by crossing two inbred parent lines,each comprising the introgression fragment(s) in homozygous orheterozygous form.

The cultivated cucumber plant may be of any type. Preferably it has goodagronomic and good fruit quality characteristics. The cultivatedcucumber plant is in one aspect uniform, both genetically andphenotypically. Especially fruit characteristics are uniform, e.g.regarding shape, skin color, skin thickness, skin ribs, skin toughness,spines (spine color, spine density, etc.), presence/absence of warts,length and diameter at edible and marketable maturity, flavour, etc.Likewise seed characteristics (i.e. characteristics of the seeds fromwhich the plant is grown) are uniform, e.g. seed size, seed color, etc.Thus, plants of the line or variety comprising QTL2.1 (or a variant)and/or QTL6.1 (or a variant) in homozygous or heterozygous form produceuniform fruits, meaning that there is little variation between fruits ofplants grown under the same environmental conditions and when fruits areat the same developmental stage (e.g. for qualitative characteristics atleast 98%, 99% or preferably 100% of all plants or plant parts, fruitsor seed are identical for the characteristics; for quantitativecharacteristics at least 90%, 95%, 98% of all plants or plant parts,fruits or seed are identical for the characteristics).

The cultivated cucumber plant comprising QTL2.1 (or a variant thereof)and/or QTL6.1 (or a variant thereof) according to the invention may beof any type, e.g. it may be of one of the following cucumber types:pickling cucumbers (e.g. American pickling, European pickling type),slicing cucumbers (e.g. American slicing), long cucumbers, shortcucumbers, European greenhouse cucumbers, Beit-Alpha type cucumbers,oriental trellis type cucumbers, Asian cucumbers (e.g. selected fromIndian Mottled cucumber, Chinese Long cucumber, Korean cucumber andJapanese cucumber type). In one aspect the cultivated cucumber accordingto the invention is an inbred line or a F1 hybrid of a pickling cucumbertype, slicing cucumber type, long cucumber type, short cucumber type,European greenhouse cucumbers, Beit-Alpha type cucumbers, orientaltrellis type cucumbers, Chinese long cucumber type, Korean cucumber typeor Japanese cucumber type. In a specific embodiment the cucumber is aninbred line or an F1 hybrid of a long cucumber, especially a Europeangreenhouse cucumber, or a short cucumber.

The plant may be a single cross F1 hybrid or an inbred line, comprisingQTL2.1 (or a variant) and/or QTL6.1 (or a variant) in homozygous orheterozygous form. In one aspect it is an F1 hybrid produced by crossingan (inbred) parent plant comprising QTL2.1 (or a variant) and/or QTL6.1(or a variant) in homozygous form with an (inbred) parent plant lackingQTL2.1 and QTL6.1 (i.e. lacking introgression fragments comprising theQTLs). Thus in one aspect the F1 hybrid is heterozygous for QTL2.1and/or QTL6.1.

In another aspect it is an F1 hybrid produced by crossing an (inbred)parent plant comprising QTL2.1 (or a variant thereof) and/or QTL6.1 (ora variant) in homozygous form with an (inbred) parent plant that alsocomprises QTL2.1 (or a variant thereof) and/or QTL6.1 (or a variant) inhomozygous form. Thus, in one aspect the F1 hybrid is homozygous forQTL2.1 and/or QTL6.1.

In one aspect the F1 hybrid is a long cucumber type, e.g. a Europeangreenhouse cucumber type, suitable for the traditional glasshousecultivation or for high-wire cultivation. In the traditional glasshousecultivation method the main stem of the plant is led up to a horizontaliron wire that is suspended at a height of about two meters above theground. When the plant reaches this height and attaches to the wire, itis “topped” by removing its growth point in order to terminate furtherproliferation, whereupon lateral shoots start to develop. These lateralshoots are allowed to grow downward to a height of about 1 meter abovethe ground, and the growth points are then removed from them. This isfollowed by flowering and the development of the fruits both on the stemand on the lateral shoots or tendrils, but the fruits on the tendrilsdevelop later than those on the stem. The fruits are harvested about 6weeks after sowing.

In the high-wire cultivation no lateral tendrils are allowed to grow andall the harvest comes from the stem. Specific varieties have beendeveloped by Nunhems which are highly suitable for high-wirecultivation, as they provide a gene called “compact”, see WO2009/059777,for example varieties High-Jack, Hi-Power, Hi-Lisa. Thus, in one aspectof the invention the cultivated cucumber plant comprises additionallythe compact gene described in WO2009/059777.

In another aspect the introgression fragment of the invention is presentin a long cucumber type, such as variety Kasja (Nunhems), which is along cucumber variety producing fruits of 27-38 cm. A “long cucumbertype” or “long cucumber plants” are greenhouse cucumbers characterizedby fruits of at least about 26 cm or 27 cm to 37 or 38 cm in length orlonger (for example 40 cm, 42 cm or more), preferably withparthenocarpic fruit formation. Examples of long cucumber types are theSabrina and Korinda varieties, or cucumber plants that are awarded ascore of 7-9 for the length of the fruit according to the CPVO Protocol(see Point 19 in Annex 1 to this protocol). Other long cucumbervarieties are, for example, Bodega, Bologna, Kamaro, Flamingo, Discover,Kalunga, Kasja, Logica, Millagon. Nicola, Milika, Manuela, Frida,Activa, Alaya, Savanna, Sienna, Bella, Sheila, Bornand.

In one aspect the European greenhouse cucumber is the plant of whichseeds were deposited under accession number NCIMB 42545, or progenythereof, whereby the progeny retain the introgression fragmentcomprising QTL2.1 and/or QTL6.1 (as detectable by the presence of one ormore markers as described elsewhere).

In another aspect the plant according to the invention is not a wildcucumber plant or a wild relative of cucumber or a landrace.

In yet another aspect the plant according to the invention is acultivated cucumber of the Eurasian cucumber group, the East Asiancucumber group or the Xishuangbanna cucumber group. In another aspectthe plant according to the invention is not a cucumber of the Indiancucumber group.

In one embodiment of the invention the cultivated cucumber plantcomprising QTL2.1 (or a variant) and/or QTL6.1 (or a variant) producesseedless fruits without pollination, i.e. is parthenocarpic. Suchseedless fruits are also encompassed herein.

In a further embodiment of the invention the cultivated cucumber plantcomprising QTL2.1 (or a variant) and/or QTL6.1 (or a variant) isprimarily gynoecious or entirely gynoecious.

In a further embodiment of the invention the cultivated cucumber plantcomprising QTL2.1 (or a variant) and/or QTL6.1 (or a variant) is uniformand genetically stable regarding the morphological characteristics ofthe fruits produced by said plant, e.g. regarding fruit shape, fruitcolor, skin thickness, warts, etc.

Fruit characteristics, such as average fruit length, average fruitdiameter, skin thickness, presence/absence of warts, spininess, skintoughness, skin color, fruit neck shape, fruit tapering, shape of medialcross section, presence or absence of seeds (parthenocarpy), etc. dependon the cucumber type, i.e. the cultivated genetic background (gene pool)into which the QTL(s) is (are) introgressed. Thus, depending on thecucumber type, various fruit shapes, sizes and fruit types are includedherein. In one aspect the fruits are seedless.

The two main types of cucumber fruit grown commercially today in theUnited States are fresh market (slicing) type and the processing(pickling) type. Varieties and production methods are typically adaptedto the end use. Slicing cucumbers are often longer, larger and havedarker and thicker skin, whereas pickling/processing cucumbers have ashorter fruit, thinner skin with interior flesh that make them moreamenable to pickling. Seedless varieties are generally preferable forboth fresh market and for pickling as developing and large seeds are notpalatable.

In one aspect the plant of the invention is a pickling type (processingtype) and produces fruits which at edible maturity and/or marketablesize have an average fruit length of at least 10 cm, or at least 11 cm,or at least 12 cm, or at least 13 cm and/or a fruit length to diameterratio of at least 2, at least 2.5, at least 3, or more.

In a different aspect the plant of the invention is a fresh market type,e.g. a long cucumber type or slicing type, and produces fruits have anaverage fruit length at edible maturity and/or marketable size which islonger than the pickling type, e.g. at least 15 cm, 16 cm, 17 cm, 18 cm,19 cm, 20 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm, 30 cm, 32 cm, 40 cm, ormore. In one aspect the fruit length/diameter ratio is at least 3.5,preferably at least 4, 5, 6, or more.

In one aspect the cucumber plant is a long cucumber type and comprisesQTL2.1 (and lacks QTL2.2) and has an average fruit length at ediblematurity and/or marketable size of at least 30 cm, preferably at least31 cm or at least 32, 33, 34, 35, 36, 37 or 38 cm. Optionally it mayfurther comprise QTL6.1. QTL2.1 and/or QTL6.1 are obtainable fromNCIMB42545.

In a preferred aspect the plant of the invention is a long cucumber typeproducing fruits of marketable size, especially seedless fruits. Thefruits of marketable size, and parts thereof, and food or feed productscontaining these, are also encompassed herein. In one embodiment the SNPmarkers are detectable in the fruits, fruit parts or food or feedproducts comprising these.

In one aspect the plant is an indeterminate cucumber. In another aspectthe cucumber is determinate.

Also seeds from which a plant according to the invention can be grown isprovided herein, as are cucumber fruits harvested from a plant accordingto the invention. These comprise the QTL(s) in their genome and cantherefore be distinguished from other fruits by the presence of one ormore of the SNP markers provided herein.

In one aspect the fruits are bitter free (selected from the groupsbitter and bitter free) at edible maturity and/or at marketable size ofthe fruits.

In a further aspect the fruit has a thin skin (selected from the groupsthick and thin) at edible maturity and/or at marketable size of thefruits.

In a different embodiment the QTL(s) is (are) introgressed into acucumber type called ‘Compact’, as described in U.S. Pat. No.8,710,303B2. Thus, the cucumber plants according to the inventioncomprise the compact gene as described in U.S. Pat. No. 8,710,303B2 inhomozygous or heterozygous form, e.g. as present in varieties Hi-Jack,Hi-Power, Hi-Lisa and others (Nunhems varieties).

A further embodiment of the invention is a plant cell, tissue or plantpart of a plant or of a seed according to the invention comprising atleast one recombinant chromosome 2 and/or at least one recombinantchromosome 6, wherein said recombinant chromosome 2 or 6 comprises anintrogression fragment from a wild relative of cucumber and wherein saidintrogression fragment comprises a QTL conferring enhanced fruit yield.

Also the use of a recombinant chromosome 2 and/or 6 comprising anintrogression fragment from a wild relative of cucumber (saidintrogression fragment comprising an allele conferring enhanced fruityield) for breeding cucumber varieties having enhanced fruit yield isencompassed herein. In one aspect said recombinant chromosomes 2 and/or6 is the recombinant chromosome 2 and/or the recombinant chromosome 6 asfound in seeds deposited under accession number NCIMB 42545, or isderived from said recombinant chromosome (e.g. is a smaller fragment ofthe introgression fragment found in said seeds).

Likewise, the use of a chromosome 2 and/or 6 as found in seeds depositedunder accession number NCIMB 42545, or in progeny thereof, forgenerating a cultivated cucumber plant comprising an introgressionfragment on said chromosome 2 and/or 6 is encompassed herein, whereinsaid introgression fragment confers enhanced fruit yield compared to thecontrol cucumber plant lacking said introgression fragment, such as thegenetic control or a control breeding line or variety. In one aspectplants grown from seeds deposited under NCIMB42345 may be used ascontrol.

Similarly the use of plants grown from seeds deposited under accessionnumber NCIMB 42545 or progeny thereof, for generating a cultivatedcucumber plant comprising enhanced fruit yield is encompassed herein,wherein said enhanced fruit yield is conferred by an introgressionfragment obtained from chromosome 2 and/or 6 of said plants or progenythereof.

Also a method for identifying (or detecting) a cultivated C. sativusvar. sativus plant or plant part comprising an introgression fragment onchromosome 2 is provided, optionally wherein said introgression fragmentis as found in NCIMB 42545 or a smaller fragment derived therefrom,comprising:

-   a) providing a cultivated C. sativus var. sativus plant or plant    parts or DNA of such plant or plant part,-   b) screening said plant, plant part or DNA using a molecular marker    assay which detects at least one SNP marker selected from the group    consisting of:    -   SNP_01 to SNP_26 for detecting the introgression fragment on        chromosome 2; and-   c) identifying and/or selecting a plant comprising:    -   i) at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more of the SNP        markers of SNP_01 to SNP_26 for detecting the introgression        fragment on chromosome 2; or    -   ii) at least 2, 3, 4 5, 6, 7, 8, 9, 10 or more consecutive        markers selected from SNP_01 to SNP_26 for detecting the        introgression fragment on chromosome 2; or    -   iii) at least 1, 2, 3, 4 5, 6, 7, 8 or more markers of a group,        said group consisting of SNP_01 to SNP_10; SNP_10 to SNP_20;        SNP_20 to SNP_26; SNP_06 to SNP_23; or    -   iv) at least 2, 3, 4 5, 6, 7, 8 or more consecutive markers of a        group, said group consisting of SNP_01 to SNP_10; SNP_10 to        SNP_20; SNP_20 to SNP_26; SNP_06 to SNP_23.

Further a method of producing C. sativus F1 hybrid plants comprising anintrogression fragment conferring enhanced fruit yield is providedcomprising:

-   a) providing a first inbred cucumber plant comprising a recombinant    chromosome 2 in homozygous form having an introgression fragment    comprising an allele conferring enhanced yield, optionally wherein    said introgression fragment is as in NCIMB 42545 or a smaller    fragment,-   b) providing a second inbred cucumber plant,-   c) crossing said cucumber plant of a) with said cucumber plant of    b),-   d) collecting F1 hybrid seeds from said cross.

The F1 hybrid seeds collected are also an embodiment of the invention.

In another aspect a method for generating progeny of NCIMB 42545 isprovided, said method comprising:

-   a) growing a plant from seeds deposited under accession number NCIMB    42545;-   b) selfing said plant one or more times and/or crossing said plant    one or more times with another cucumber plant to generate progeny    seeds;-   c) screening said progeny seeds or plants grown from said seeds or    parts of the seeds or plants using a molecular marker assay which    detects at least one SNP marker selected from the group consisting    of: SNP_01 to SNP_26 for detecting the introgression fragment on    chromosome 2;-   d) identifying and/or selecting a progeny plant comprising:    -   i) at least 1 of the SNP markers of SNP_01 to SNP_26 for        detecting the introgression fragment on chromosome 2; or    -   ii) at least 2, 3, or 4 consecutive markers selected from SNP_1        to SNP_26 for detecting the introgression fragment on chromosome        2; or    -   iii) at least 1, 2, or 3 markers of a group of markers        consisting of SNP_1 to SNP_10; SNP_10 to SNP_20; SNP_20 to        SNP_26; SNP_06 to SNP_23 for detecting the introgression        fragment on chromosome 2; or    -   iv) at least 2, 3 or 4 consecutive markers of a group of markers        consisting of SNP_1 to SNP_10; SNP_10 to SNP_20; SNP_20 to        SNP_26; SNP_06 to SNP_23 for detecting the introgression        fragment on chromosome 2.

The cucumber plant in step b is preferably a cultivated cucumber, suchas a European greenhouse cucumber or long cucumber type.

The method optionally further comprises the step of identifying aprogeny plant having enhanced fruit yield compared to the control.

A progeny plant generated by the above method is also an aspect of theinvention. The progeny plant may comprise a shorter introgressionfragment than the one found in NCIMB 42545, which retains the QTL2.1.

Also a method for identifying (or detecting) a cultivated C. sativusvar. sativus plant or plant part comprising an introgression fragment onchromosome 6 is provided, optionally wherein said introgression fragmentis as found in NCIMB 42545 or a smaller fragment derived therefrom,comprising:

-   a) providing a cultivated C. sativus var. sativus plant or plant    parts or DNA of such plant or plant part,-   b) screening said plant, plant part or DNA using a molecular marker    assay which detects at least one SNP marker selected from the group    consisting of:    -   SNP_27 to SNP_40 for detecting the introgression fragment on        chromosome 6; and-   c) identifying and/or selecting a plant comprising:    -   i) at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more of the SNP        markers of SNP_27 to SNP_40 for detecting the introgression        fragment on chromosome 6; or    -   ii) at least 2, 3, 4 5, 6 7, 8, 9, 10 or more consecutive        markers selected from SNP_27 to SNP_40 for detecting the        introgression fragment on chromosome 6; or    -   iii) at least 1, 2, 3, 4 5, 6 or more markers of a group, said        group consisting of SNP_27 to SNP_33; SNP_33 to SNP_40; SNP_29        to SNP_38; or    -   iv) at least 2, 3, 4 5, 6, 7, 8 or more consecutive markers of a        group, said group consisting of SNP_27 to SNP_33; SNP_33 to        SNP_40; SNP_29 to SNP_38.

Further a method of producing C. sativus F1 hybrid plants comprising anintrogression fragment conferring enhanced fruit yield is providedcomprising:

-   a) providing a first inbred cucumber plant comprising a recombinant    chromosome 6 in homozygous form having an introgression fragment    comprising an allele conferring enhanced yield, optionally wherein    said introgression fragment is as in NCIMB 42545 or a smaller    fragment,-   b) providing a second inbred cucumber plant,-   c) crossing said cucumber plant of a) with said cucumber plant of    b),-   d) collecting F1 hybrid seeds from said cross.

The F1 hybrid seeds collected are also an embodiment of the invention.

In another aspect a method for generating progeny of NCIMB 42545 isprovided, said method comprising:

-   a) growing a plant from seeds deposited under accession number NCIMB    42545;-   b) selfing said plant one or more times and/or crossing said plant    one or more times with another cucumber plant to generate progeny    seeds;-   c) screening said progeny seeds or plants grown from said seeds or    parts of the seeds or plants using a molecular marker assay which    detects at least one SNP marker selected from the group consisting    of:    -   SNP_27 to SNP_40 for detecting the introgression fragment on        chromosome 6;-   d) identifying and/or selecting a progeny plant comprising:    -   i) at least 1 of the SNP markers of SNP_27 to SNP_40 for        detecting the introgression fragment on chromosome 6; or    -   ii) at least 2, 3, or 4 consecutive markers selected from SNP_27        to SNP_40 for detecting the introgression fragment on chromosome        6; or    -   iii) at least 1, 2, or 3 markers of a group of markers        consisting of SNP_27 to SNP_33; SNP_33 to SNP_40; SNP_29 to        SNP_38; for detecting the introgression fragment on chromosome        6; or    -   iv) at least 2, 3 or 4 consecutive markers of a group of markers        consisting of SNP_27 to SNP_33; SNP_33 to SNP_40; SNP_29 to        SNP_38 for detecting the introgression fragment on chromosome 6.

The cucumber plant in step b is preferably a cultivated cucumber, suchas a European greenhouse cucumber or long cucumber type.

The method optionally further comprises the step of identifying aprogeny plant having enhanced fruit yield compared to the control.

A progeny plant generated by any of the above methods is also an aspectof the invention. The progeny plant may comprise a shorter introgressionfragment than the one found in NCIMB 42545, which retains the QTL2.1and/or QTL6.1.

Also containers and packages containing or comprising seeds from whichplants of the invention can be grown are provided herein. These may belabelled as containing cultivated cucumber seeds producing enhanced orhigh fruit yield.

Also progeny seeds and progeny plants of plants of the invention areprovided, which retain the introgression on chromosome 2 and/or 6comprising the yield QTL(s), or which comprise a smaller introgression(e.g. derivable from the introgression fragment as is present in NCIMB42545) which still confers enhanced yield. Progeny may be any generationobtained by selfing a cucumber plant according to the invention and/orcrossing a cucumber plant according to the invention with anothercucumber plant one or more times. Progeny are, therefore, either thegeneration (seeds) produced from the first cross (F1) or selfing (S1),or any further generation produced by crossing and/or selfing (F2, F3,etc.) and/or backcrossing (BC1, BC2, etc.) one or more selected plantsof the F1 and/or S1 and/or BC1 generation (or plants of any furthergeneration, e.g. the F2) with another cucumber plant (and/or with a wildrelative of cucumber). Progeny are preferably selected to retain therecombinant chromosome 2 and/or 6 comprising the introgression fragmentfrom a wild relative of cucumber (comprising the yield QTL(s)). Thusprogeny also have the increased yield phenotype, preferably at least thesame yield as the plant used in the initial cross or selfing. Thepresence of (or retention of) the introgression fragment comprising theQTL can be determined phenotypically and/or using the molecular markerassay(s) described herein. Regarding phenotypic assessment, of courseconsideration needs to be given to the dominance nature of the QTL.

In a further aspect parts of the cucumber plants according to theinvention are provided. Parts include for example cells andcell-cultures, tissue cultures, vegetative plant tissues (leaves, roots,etc.), flowers, pollen, embryos, fruits, parts of fruits, etc. The plantparts comprise the introgression fragment on chromosome 2 and/or 6, asdescribed, and as can be detected using one or more of the markersdescribed. Also, when whole plants are regenerated from such cucumberparts, such as cells, cell- or tissue cultures, the regenerated plantscomprise the recombinant chromosome 2 and/or 6 and the yield phenotype.

Thus, also provided is a plant cell, tissue or plant part of a plant orof a seed according the invention comprising at least one recombinantchromosome 2 and/or 6, wherein said recombinant chromosome 2 and/or 6comprises an introgression fragment from a wild relative of cucumberplant and wherein said introgression fragment comprises an alleleconferring enhanced fruit yield.

Also in vitro cell cultures and in vitro tissue cultures are encompassedherein, of cells or tissues comprising a recombinant chromosome 2 and/or6 described. Preferably the cells or tissues can be regenerated into awhole cucumber plant, i.e. the cells are regenerable cells and thetissues comprise regenerable cells. Thus, also vegetative propagationsof the plants according to the invention are an embodiment herein. Thus,a vegetatively propagated cultivated cucumber plant is provided whichcomprises a recombinant chromosome 2 and/or 6 as described herein. In adifferent aspect non-propagating cells comprising QTL2.1 and/or QTL6.1are encompassed herein, as are tissues comprising such cells.

In a specific aspect a cucumber fruit harvested from a plant accordingto the invention is provided. Marketable cucumber fruits, especially forthe fresh market (slicing), are generally graded according to fruit sizeand quality characteristics after harvest. See e.g. the United StatesStandards for Grades of Cucumbers, US Department of Agriculture,Effective Mar. 1, 1985 and reprinted January 1997. Herein differentgrades of cucumbers are distinguished. Thus, in one aspect harvestedfruits are provided of U.S. Fancy grade, U.S. Extra No. 1 grade, U.S.No. 1 grade, U.S. No. 1 Small grade, U.S. No. 1 Large grade, U.S. No. 2grade. Also containers or packages comprising or consisting of harvestedcucumber fruits are provided. Again, the cells of the fruits aredistinguishable from other cucumber fruits by the presence of therecombinant chromosome 2 and/or 6 (as determinable in one or more of themolecular marker assays).

In another aspect the cucumber is a long cucumber type and fruitsharvested and optionally processed (e.g. sliced or diced) are provided.

In another aspect the cucumber is a pickling type and fruits harvestedand optionally pickled are provided.

The invention also provides for a food or feed product comprising orconsisting of a plant part described herein preferably a cucumber fruitor part thereof and/or an extract from a plant part described herein.The food or feed product may be fresh or processed, e.g., pickled,canned, steamed, boiled, fried, blanched and/or frozen, etc. Forexample, containers such as cans, boxes, crates, bags, cartons, ModifiedAtmosphere Packaging, films (e.g. biodegradable films), etc. comprisingplant parts such as fruits or fruit parts (fresh and/or processed)described herein are also provided herein.

Methods and Uses According to the Invention

In a further embodiment, the invention provides for a method ofproducing a new cultivated cucumber plant which comprises anintrogression fragment on chromosome 2 and/or 6 (which confers enhancedyield) in homozygous or heterozygous form, as described. The methodcomprises crossing a plant of the invention, or a progeny plant thereof,either as male or as female parent, with a second cucumber plant (or awild relative of cucumber) one or more times, and/or selfing a cucumberplant according to the invention, or a progeny plant thereof, one ormore times, and selecting progeny from said crossing and/or selfing.

Thus, a method for transferring the recombinant chromosome 2 and/or 6,comprising the yield QTL2.1 and/or QTL6.1 respectively, from one(cultivated) cucumber plant into another (cultivated) cucumber plant isprovided, especially into cucumber varieties or breeding lines for whichthe fruit yield should be increased.

The method comprises the steps of:

-   a) providing a first cultivate cucumber plant comprising a    recombinant chromosome 2 and/or 6 having an introgression fragment    comprising an allele conferring enhanced fruit yield in homozygous    form, b) providing a second cultivated cucumber plant, especially a    plant having a wild type (non-recombinant) chromosome 2 and/or 6,-   c) crossing said cucumber plant of a) with said cucumber plant of    b),-   d) collecting F1 hybrid seeds from said cross, and-   e) optionally selfing the plant grown from said F1 hybrid seeds to    produce F2 seeds or further selfing generations, and optionally    selecting the F2 seeds or further selfing generation seeds having    the recombinant chromosome 2 and/or 6, and-   f) optionally breeding further with plants grown from said F1 or F2    or further generation selfing seeds to produce a cucumber plant    having good agronomic characteristics and comprising the    introgression fragment in homozygous or heterozygous form.

The presence or absence of the recombinant chromosome 2 and/or 6, and ofthe introgression fragment, may be determined by one or more of themolecular marker assays described herein and/or by determining whetherthe yield is significantly increased compared to the plant of step b).Further breeding in step f) may comprise selfing, crossing, doublehaploid production, backcrossing, and combinations thereof (e.g.backcrossing and selfing), etc. Plants, plant parts and seeds obtainableby the above method are encompassed herein. In one aspect the plant ofstep a) may be a plant grown from seeds deposited under NCIMB42545, orprogeny thereof, or a plant comprising the introgression fragment onchromosome 2 and/or 6 as present in seeds deposited under NCIMB42545, ora shorter fragment of that fragment.

Also provided is a method of producing cultivated cucumber F1 hybridplants comprising a yield QTL on chromosome 2 and/or 6 comprising:

-   a) providing a first inbred cucumber plant comprising at least one    recombinant chromosome 2 and/or 6 comprising an introgression    fragment comprising a yield QTL selected from QTL2.1 or a variant    thereof and/or QTL6.1 or a variant thereof,-   b) providing a second inbred cucumber plant either lacking QTL2.1    and QTL6.1; or comprising at least one recombinant chromosome 2    and/or 6 comprising an introgression fragment comprising a yield QTL    selected from QTL2.1 or a variant thereof and/or QTL6.1 or a variant    thereof,-   c) crossing said cucumber plant of a) with said cucumber plant of    b),-   d) collecting F1 hybrid seeds from said cross.

The inbred cucumber plant of a) and b) may be homozygousand/orheterozygous for the introgression fragment on chromosome 2 and/or 6,and they may contain introgression fragments of different sizes and/orof different origin, i.e. from different wild relatives of cucumber. So,for example the introgression fragment in a) may be the same or adifferent introgression fragment than in b). In one aspect the inbredcucumber plant of a) comprises QTL2.1 or a variant thereof and/or QTL6.1or a variant thereof in homozygous form and/or the inbred cucumber plantof b) comprises QTL2.1 or a variant and/or QTL6.1 or a variant thereofthereof in homozygous form. In one aspect the introgression fragmentcomprising QTL2.1 and/or QTL6.1 is the fragment as found in NCIMB42545or a smaller fragment thereof.

In one embodiment plants grown from line NCIMB42545, or progeny thereof,e.g. obtained by selfing and/or crossing and retaining QTL2.1 and/orQTL6.1 preferably in homozygous form, are used as a parent line for F1hybrid seed production.

The F1 hybrid seeds preferably comprise at least one recombinantchromosome 2 and/or 6 and the F1 plants grown from the seeds dotherefore produce enhanced fruit yield compared to the control, e.g. thegenetic control.

Plants and seeds obtainable by the above method are encompassed herein.

In a different aspect a method for producing a cultivated cucumber plantcomprising an introgression fragment on chromosome 2 and/or 6, whereinsaid introgression fragment comprises a yield QTL, is provided, saidmethod comprising the steps:

-   a) providing a first cultivated cucumber plant,-   b) providing a second wild relative of cucumber, wherein said plant    comprises QTL2.1 (or a variant thereof) and/or QTL6.1 (or a variant    thereof) as determinable by the presence of one or more SNP markers    as described herein,-   c) crossing said cucumber plant of a) with said cucumber plant of    b),-   d) collecting F1 seeds from said cross and backcrossing an F1 plant    to the cucumber plant of a) to produce a backcross (BC1) population,    or selfing said F1 plants one or more times to produce an F2 or F3    or higher generation selfing population,-   e) optionally backcrossing a plant of d) one or more times to the    cucumber plant of a) to produce a higher generation backcross    population, and-   f) identifying a F2, F3, or higher generation selfing, or BC1 or    higher generation backcross plant which comprises an introgression    on chromosome 2 and/or 6, wherein said introgression fragment    comprises QTL2.1 (or a variant thereof) and/or QTL6.1 (or a variant    thereof).

When referring to backcross populations in the method, the backcrosspopulations may also be selfed, i.e. BC1S1, BC1S2, BC2S1, BC2S2, orothers.

In one or more of steps b) to f) the presence of the QTL (or theintrogression fragment comprising the QTL) may be tested (and plants maybe selected) by carrying out a molecular marker assay as describedelsewhere herein.

Using this method, one can generate and/or select new cultivatedcucumber plants comprising an introgression with QTL 2.1 (or a variant)and/or QTL6.1 (or a variant thereof) from a wild source, such as a wildrelative of cucumber. In one aspect both QTLs are from the sameaccession of wild relative of cucumber.

In one aspect the method for producing a cultivated cucumber plantcomprising an introgression fragment on chromosome 2 and/or chromosome6, wherein said introgression fragment(s) comprise(s) a yield QTL,comprises the steps:

-   a) providing a first cultivated cucumber plant,-   b) providing a second wild relative of cucumber comprising one or    more of the SNP markers provided herein,-   c) crossing said plant of a) with said plant of b),-   d) collecting F1 seeds from said cross and backcrossing an F1 plant    to the cucumber plant of a) to produce a backcross (BC1) population,    or selfing said F1 plants one or more times to produce an F2 or F3    population,-   e) optionally selfing the backcross population to produce e.g. a    BC1S1 or BC1S2 population,-   f) identifying a F2, F3, BC1, BC1S1, or BC1S2 plant which comprises    the (one or more) SNP markers and/or any wild-relative of cucumber    genome-specific marker in between the SNP markers.

Also provided is a method for identifying a wild relative of cucumbercomprising a yield QTL on chromosome 2, said method comprising:

-   A) providing a wild relative of cucumber accession or several    accessions;-   B) screening said accession(s) using a molecular marker assay which    detects at least one (or at least 2, 3, 4, 5, 6, 7, 8, 9, 10 or    more) SNP marker selected from the group consisting of: SNP_01 to    SNP_26 (or of subgroups of SNP markers, such as SNP_01 to SNP_10;    SNP_10 to SNP_20; SNP_20 to SNP_26; SNP_06 to SNP_23);-   C) identifying and/or selecting an accession from b) comprising at    least one or more of the following markers:-   a) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_01 in SEQ ID NO: 1 (or in a variant thereof);-   b) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_02 in SEQ ID NO: 2 (or in a variant thereof);-   c) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_03 in SEQ ID NO: 3 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_04 in SEQ ID NO: 4 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_05 in SEQ ID NO: 5 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_06 in SEQ ID NO: 6 (or in a variant thereof);-   g) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_07 in SEQ ID NO: 7 (or in a variant thereof);-   h) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_08 in SEQ ID NO: 8 (or in a variant thereof);-   i) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_09 in SEQ ID NO: 9 (or in a variant thereof);-   j) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_10 in SEQ ID NO: 10 (or in a variant thereof);-   k) the GG or AG genotype for the Single Nucleotide Polymorphism    marker SNP_11 in SEQ ID NO: 11 (or in a variant thereof);-   l) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_12 in SEQ ID NO: 12 (or in a variant thereof);-   m) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_13 in SEQ ID NO: 13 (or in a variant thereof);-   n) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_14 in SEQ ID NO: 14 (or in a variant thereof);-   o) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_15 in SEQ ID NO: 15 (or in a variant thereof);-   p) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_16 in SEQ ID NO: 16 (or in a variant thereof);-   q) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_17 in SEQ ID NO: 17 (or in a variant thereof);-   r) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_18 in SEQ ID NO: 18 (or in a variant thereof);-   s) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_19 in SEQ ID NO: 19;-   t) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_20 in SEQ ID NO: 20 (or in a variant thereof);-   u) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_21 in SEQ ID NO: 21 (or in a variant thereof);-   v) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_22 in SEQ ID NO: 22 (or in a variant thereof);-   w) the TT or TG genotype for the Single Nucleotide Polymorphism    marker SNP_23 in SEQ ID NO: 23 (or in a variant thereof);-   x) the GG or GT genotype for the Single Nucleotide Polymorphism    marker SNP_24 in SEQ ID NO: 24 (or in a variant thereof);-   y) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_25 in SEQ ID NO: 25 (or in a variant thereof);-   z) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_26 in SEQ ID NO: 26 (or in a variant thereof);-   aa) any wild relative of cucumber genome-specific marker in between    marker SNP_01 and SNP_26; and optionally-   D) introgressing said QTL from said wild accession into cultivated    cucumber (e.g. by backcrossing).

In step B), C) and D) also other molecular marker tests describedelsewhere herein can be used. With this method one can, thus, screenwild relatives of cucumber for the presence of one or more of themarkers and, thus, the presence of QTL2.1 (or a variant thereof) andintrogress the QTL into cultivated cucumber plants. Plants and seedsobtained by this method are also an embodiment of the invention.

Also provided is a method for identifying a wild relative of cucumbercomprising a yield QTL on chromosome 6, said method comprising:

-   A) providing a wild relative of cucumber accession or several    accessions;-   B) screening said accession(s) using a molecular marker assay which    detects at least one (or at least 2, 3, 4, 5, 6, 7, 8, 9, 10 or    more) SNP marker selected from the group consisting of: SNP_27 to    SNP_40 (or of subgroups of SNP markers, such as SNP_27 to SNP_33;    SNP_33 to SNP_40; SNP_29 to SNP_38);-   C) identifying and/or selecting an accession from b) comprising at    least one or more of the following markers:-   a) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_27 in SEQ ID NO: 27 (or in a variant thereof);-   b) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_28 in SEQ ID NO: 28 (or in a variant thereof);-   c) the CC or CA genotype for the Single Nucleotide Polymorphism    marker SNP_29 in SEQ ID NO: 29 (or in a variant thereof);-   d) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_30 in SEQ ID NO: 30 (or in a variant thereof);-   e) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_31 in SEQ ID NO: 31 (or in a variant thereof);-   f) the CC or CT genotype for the Single Nucleotide Polymorphism    marker SNP_32 in SEQ ID NO: 32 (or in a variant thereof);-   g) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_33 in SEQ ID NO: 33 (or in a variant thereof);-   h) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_34 in SEQ ID NO: 34 (or in a variant thereof);-   i) the GG or GA genotype for the Single Nucleotide Polymorphism    marker SNP_35 in SEQ ID NO: 35 (or in a variant thereof);-   j) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_36 in SEQ ID NO: 36 (or in a variant thereof);-   k) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_37 in SEQ ID NO: 37 (or in a variant thereof);-   l) the AA or AG genotype for the Single Nucleotide Polymorphism    marker SNP_38 in SEQ ID NO: 38 (or in a variant thereof);-   m) the AA or AC genotype for the Single Nucleotide Polymorphism    marker SNP_39 in SEQ ID NO: 39 (or in a variant thereof);-   n) the TT or TC genotype for the Single Nucleotide Polymorphism    marker SNP_40 in SEQ ID NO: 40 (or in a variant thereof).-   o) any wild relative of cucumber genome-specific marker in between    marker SNP_27 and SNP_40.    -   and optionally-   D) introgressing said QTL from said wild accession into cultivated    cucumber (e.g. by backcrossing).

In step B), C) and D) also other molecular marker tests describedelsewhere herein can be used. With this method one can, thus, screenwild relatives of cucumber for the presence of one or more of themarkers and, thus, the presence of QTL6.1 (or a variant thereof) andintrogress the QTL into cultivated cucumber plants. Plants and seedsobtained by this method are also an embodiment of the invention.

In still another aspect a method for identifying a cultivated cucumberplant comprising an introgression fragment on chromosome 2 and/or 6,wherein said introgression fragment comprises a yield QTL, is provided,said method comprising: screening a cultivated cucumber plant or apopulation of cultivated cucumber plants or parts of such cucumberplants (e.g. fruits, cells, DNA) using a molecular marker assay whichdetects at least one SNP marker (preferably 2, 3, 4, 5 or more;preferably consecutive SNP markers) indicative of (linked to) QTL2.1and/or QTL6.1 as described elsewhere herein.

In this method any of the molecular marker tests described elsewhereherein can be used. Thus, using this method one can detect the presenceof an introgression fragment on chromosome 2 and/or 6 and comprisingQTL2.1 and/or QTL.1 in cultivated cucumber plants or plant parts.

In yet another aspect a method for detecting whether a cultivatedcucumber plant comprises an introgression fragment on chromosome 2,wherein said introgression fragment comprises QTL2.1, is provided, saidmethod comprising:

-   a) providing cultivated cucumber plant or a plant part,-   b) screening said plant or said plant part (or DNA obtained from    said plant or plant part) using a molecular marker assay which    detects at least one (preferably at least 2, 3, 4, 5 or more) SNP    marker selected from the group consisting of:    -   SNP_01 to SNP_26 and/or any wild-relative of cucumber        genome-specific marker in between the marker SNP_01 and SNP_26.

In yet another aspect a method for detecting whether a cultivatedcucumber plant comprises an introgression fragment on chromosome 6,wherein said introgression fragment comprises QTL6.1, is provided, saidmethod comprising:

-   a) providing cultivated cucumber plant or a plant part,-   b) screening said plant or said plant part (or DNA obtained from    said plant or plant part) using a molecular marker assay which    detects at least one (preferably at least 2, 3, 4, 5 or more) SNP    marker selected from the group consisting of:    -   SNP_27 to SNP_40 and/or any wild-relative of cucumber        genome-specific marker in between the marker SNP_27 and SNP_40.

Molecular marker screening obviously involves obtaining plant materialand analyzing the genomic DNA of the material for the marker genotype.

In this method also other molecular marker tests described elsewhereherein can be used.

Also encompassed herein is a method for producing a cultivated cucumberplant comprising an introgression fragment on chromosome 2, wherein saidintrogression fragment comprises QTL2.1, comprising:

-   a) providing a first cultivated cucumber plant lacking an    introgression fragment comprising QTL2.1, b) providing a second    cultivated cucumber plant selected from plants grown from seeds    deposited under accession number NCIMB42545 or progeny thereof,-   c) crossing said plant of a) with said plant of b),-   d) collecting F1 seeds from said cross and optionally selfing said    F1 plants one or more times to produce an F2 or F3 or further    selfing population,-   e) optionally backcrossing the F1 plant or an F2 or F3 or further    selfing plant to the plant of a) to produce a backcross population,-   f) optionally selfing the backcross population one or more times,-   g) identifying a F1, F2, F3, further selfing or backcross plant    which comprises one or more or all of the SNP marker genotypes    indicative of the introgression fragment on chromosome 2.

Also encompassed herein is a method for producing a cultivated cucumberplant comprising an introgression fragment on chromosome 6, wherein saidintrogression fragment comprises QTL6.1, comprising:

-   a) providing a first cultivated cucumber plant lacking an    introgression fragment comprising QTL6.1, b) providing a second    cultivated cucumber plant selected from plants grown from seeds    deposited under accession number NCIMB42545 or progeny thereof,-   c) crossing said plant of a) with said plant of b),-   d) collecting F1 seeds from said cross and optionally selfing said    F1 plants one or more times to produce an F2 or F3 or further    selfing population,-   e) optionally backcrossing the F1 plant or an F2 or F3 or further    selfing plant to the plant of a) to produce a backcross population,-   f) optionally selfing the backcross population one or more times,-   g) identifying a F1, F2, F3, further selfing or backcross plant    which comprises one or more or all of the SNP marker genotypes    indicative of the introgression fragment on chromosome 6.

In a further aspect a method of producing F1 hybrid plants is providedcomprising:

-   a) providing a first inbred cucumber plant comprising at least one    recombinant chromosome 2 having an introgression fragment comprising    QTL2.1, wherein said introgression fragment is the fragment as found    in NCIMB42545, or a shorter fragment of that introgression fragment,-   b) providing a second inbred cucumber plant with or without a    recombinant chromosome 2,-   c) crossing said plant of a) with said plant of b),-   d) collecting F1 hybrid seeds from said cross.

In a further aspect a method of producing F1 hybrid plants is providedcomprising:

-   a) providing a first inbred cucumber plant comprising at least one    recombinant chromosome 6 having an introgression fragment comprising    QTL6.1, wherein said introgression fragment is the fragment as found    in NCIMB42545, or a shorter fragment of that introgression fragment,-   b) providing a second inbred cucumber plant with or without a    recombinant chromosome 6,-   c) crossing said plant of a) with said plant of b),-   d) collecting F1 hybrid seeds from said cross.

In another aspect a method for generating progeny of NCIMB42545retaining QTL2.1 and/or QTL6.1 is provided, said method comprising:

-   a) growing a plant from seeds deposited under accession number    NCIMB42545;-   b) selfing said plant one or more times or crossing said plant one    or more times with another cultivated cucumber plant to generate    progeny seeds;-   c) screening said progeny seeds or plants grown from said seeds or    parts of the seeds or plants using a molecular marker assay which    detects at least one SNP marker disclosed herein;-   d) identifying and/or selecting a progeny plant comprising at least    one, two, three or more of the SNP markers indicative of the    introgression fragment comprising the QTL2.1 and/or QTL6.1 (as    described elsewhere herein); and-   e) optionally confirming the enhanced fruit yield of said progeny    plants.

In one aspect the yield in e) is preferably at least the same yield asfor plants grown from NCIMB42545 when grown under the same conditions.

A method for generating progeny of NCIMB 42545 is provided, said methodcomprising:

-   -   a) growing a plant from seeds deposited under accession number        NCIMB 42545;    -   b) selfing said plant one or more times or crossing said plant        one or more times with another cucumber plant to generate        progeny seeds;    -   c) screening said progeny seeds or plants grown from said seeds        or parts of the seeds or plants using a molecular marker assay        which detects at least one SNP marker selected from the group        consisting of:        -   SNP_01 to SNP_26 for detecting the introgression fragment on            chromosome 2; and/or        -   SNP_27 to SNP_40 for detecting the introgression fragment on            chromosome 6;    -   d) identifying and/or selecting a progeny plant comprising:        -   i) at least 1 of the SNP markers of SNP_01 to SNP_26 for            detecting the introgression fragment on chromosome 2 and/or            at least 1 of the SNP markers of SNP_27 to SNP_40 for            detecting the introgression fragment on chromosome 6; or        -   ii) at least 2, 3, or 4 consecutive markers selected from            SNP_01 to SNP_26 for detecting the introgression fragment on            chromosome 2 and/or at least 2, 3, or 4 consecutive markers            selected from SNP_27 to SNP_40 for detecting the            introgression fragment on chromosome 6, and    -   e) optionally confirming the enhanced fruit yield of said        progeny plants.

A progeny plant generated by any of the above methods is also an aspectof the invention.

One can also use the methods and the markers described herein to reducethe size of the introgression fragment comprising the QTL2.1 and/orQTL6.1, i.e. to generate and select recombinants having a smallerintrogression fragment on chromosome 2 and/or 6, but which retain theyield enhancing part of the introgression fragment.

In one aspect the invention encompasses the use of a recombinantchromosome 2 and/or 6 comprising an introgression fragment from a wildrelative of cucumber, said introgression fragment comprising a yieldQTL, for breeding cucumber varieties having enhanced fruit yield.

Also provided is the use of a chromosome 2 and/or 6 as found in seedsdeposited under accession number NCIMB42545 or progeny thereof forgenerating cultivated cucumber plant comprising an introgressionfragment of said chromosome 2 and/or 6.

Also provided is the use of plants grown from seeds deposited underaccession number NCIMB 42545, or progeny thereof, for generating acultivated cucumber plant comprising enhanced fruit yield, wherein saidenhanced fruit yield is conferred by an introgression fragment obtainedfrom chromosome 2 and/or 6 of said plants or progeny.

DNA and Chromosomes According to the Invention

In one aspect a modified (recombinant) cultivated cucumber chromosome 2and/or 6 is provided herein, which comprises an introgression fragmentof a wild relative of cucumber, as described throughout thespecification. In one aspect the recombinant chromosome is isolated fromits natural environment. In another aspect it is in a plant cell,especially in a cucumber cell, especially in a cultivated cucumber cell.Also an isolated part of the recombinant chromosome comprising the QTLis provided herein.

In a further aspect a recombinant nucleic acid molecule, especially arecombinant DNA molecule, is provided which comprises a yield-alleleaccording to the invention. In one aspect the yield-allele is detectableby one or more of the molecular marker assays described herein. Also aDNA vector is provided comprising the recombinant DNA. The recombinantDNA molecule or DNA vector may be an isolated nucleic acid molecule. TheDNA comprising the yield-allele may be present in a microorganisms, suchas a bacterium (e.g. Agrobacterium).

The use of such a (isolated or extracted) nucleic acid molecule and/orof such a recombinant chromosome or part thereof for generating plantcells and plants comprising a yield-allele is encompassed herein. In oneaspect it may be used to generate transgenic plant cells and transgenicplants, e.g. cucumber cells, cucumber plants and parts (e.g. fruits)comprising the yield allele and the plant comprises an enhanced fruityield phenotype.

Thus, transgenic plant cells, e.g. transgenic cucumber cells, comprisingin their genome a recombinant chromosome 2 and/or 6 as described and/ora recombinant nucleic acid molecule comprising a yield-allele are alsoan embodiment of the invention. In one aspect the DNA moleculecomprising the yield-allele is stably integrated into the cucumbergenome.

The yield-allele may also be cloned and a chimeric gene may be made,e.g. operably linking a plant expressible promoter to the yield allele.Such a chimeric gene may be introduced into a plant cell and the plantcell may be regenerated into a whole plant to produce a transgenicplant. In one aspect the transgenic plant is a cucumber plant, or amelon plant.

Thus, transgenic plants, especially transgenic cultivated cucumber ormelon plants, comprising a yield allele and having increased fruit yieldare provided herein.

Especially cells or cell cultures comprising a recombinant chromosome 2and/or 6 according to the invention are an embodiment, independentwhether the recombinant chromosome 2 and/or 6 is introduced bytransgenic methods or by breeding methods. The cells are e.g. in vitroand are regenerable into plants comprising the recombinant chromosome 2and/or 6 of the invention.

Also the molecular marker sequences (and isolated nucleic acid moleculescomprising the sequence) disclosed herein and molecular markers inbetween any of the mentioned molecular markers described herein, linkedto the yield QTL2.1 and/or QTL6.1, and their use in detecting and/orgenerating cucumber plants comprising said QTLs are encompassed herein.

In one aspect, the introgression fragment comprising QTL2.1 and/orQTL6.1 is from a different wild donor than the introgression fragmentsdescribed in WO2016/059090 and WO2016/059092 and present in the seedsdeposited therein under accession number NCIMB42262. Thus in one aspectQTL2.1 and/or QTL6.1 of the instant invention are not obtainable fromseeds deposited under accession number NCIMB42262.

Plants according to the invention do, in one embodiment, not comprisethe recessive little leaf (‘ll’) allele as found in Arkansas Little Leafand line H-19.

SEED DEPOSITS

A representative sample of seeds of a BC1S3 Cucumis sativus var. sativusline of the long cucumber type, designated CUCYLD2-6, comprising anintrogression fragment comprising QTL2.1 and an introgression fragmentcomprising QTL6.1 in homozygous form, and a genetic control (GC) lackingany introgression fragments and lacking the yield QTLs, designatedCUYLD-GC, were deposited by Nunhems B.V. on 18 Feb. 2016 and on 17 Dec.2014, respectively, at the NCIMB Ltd. (Ferguson Building, CraibstoneEstate, Bucksburn Aberdeen, Scotland AB21 9YA, UK) according to theBudapest Treaty, under the Expert Solution (EPC 2000, Rule 32(1)). Seedswere given the following deposit numbers NCIMB42545 (CUCYLD2-6) andNCIMB 42345 (CUYLD-GC). It is noted that the seeds deposited underaccession number NCIMB42545 do, on chromosome 2, not contain thenegative yield QTL (QTL2.2) which was originally found closely linked tothe positive yield QTL of the invention.

The Applicant requests that samples of the biological material and anymaterial derived therefrom be only released to a designated Expert inaccordance with Rule 32(1) EPC or related legislation of countries ortreaties having similar rules and regulation, until the mention of thegrant of the patent, or for 20 years from the date of filing if theapplication is refused, withdrawn or deemed to be withdrawn.

Access to the deposit will be available during the pendency of thisapplication to persons determined by the Director of the U.S. PatentOffice to be entitled thereto upon request. Subject to 37 C.F.R. § 1.808(b), all restrictions imposed by the depositor on the availability tothe public of the deposited material will be irrevocably removed uponthe granting of the patent. The deposit will be maintained for a periodof 30 years, or 5 years after the most recent request, or for theenforceable life of the patent whichever is longer, and will be replacedif it ever becomes nonviable during that period. Applicant does notwaive any rights granted under this patent on this application or underthe Plant Variety Protection Act (7 USC 2321 et seq.).

The following non-limiting Examples describe how one can obtain plantsaccording to the invention, comprising QTL2.1 and/or QTL6.1. Unlessstated otherwise in the Examples, all recombinant DNA techniques arecarried out according to standard protocols as described in Sambrook etal. (1989) Molecular Cloning: A Laboratory Manual, Second Edition, ColdSpring Harbor Laboratory Press, and Sambrook and Russell (2001)Molecular Cloning: A Laboratory Manual, Third Edition, Cold SpringHarbor Laboratory Press, NY; and in Volumes 1 and 2 of Ausubel et al.(1994) Current Protocols in Molecular Biology, Current Protocols, USA.Standard materials and methods for plant molecular work are described inPlant Molecular Biology Labfax (1993) by R.D.D. Croy, jointly publishedby BIOS Scientific Publications Ltd (UK) and Blackwell ScientificPublications, UK. Standard breeding methods are described in ‘Principlesof Plant breeding’, Second Edition, Robert W. Allard (ISBN0-471-02309-4).

EXAMPLES Example 1—Identification of Yield QTLs Population Development

A wild relative of cucumber accession (hereinafter the donor), obtainedfrom the USA, was crossed with a proprietary long cucumber breedingline, HMRKC, in the breeding program for the North-European andNorth-American greenhouse cucumber market. HMRKC is an elite line forthe long greenhouse cucumber program.

A QTL-discovery population has been developed out of the cross betweenHMRKC and the wild accession. During population development only femaleflowering plants have been kept as to facilitate yield measurements.

SNP markers have been used during several generations to select for longfruits and to optimize for genome coverage and homozygosity. A BC2S2population was used to construct a genetic map.

220 BC2S2 plants were self-pollinated to generate BC2S3's. The BC2S2plants were also crossed with an elite line from the breeding program,line CUZL0176, to create test hybrids for the North-European market.

The 220 test-hybrids have been used in yield trials in the Netherlands.Also a genetic control was generated by crossing HMRKC with CUZL0176.The 220 test hybrids and the genetic control were used in yield trialsin the Netherlands.

The same 220 BC2S2 plants were crossed with another elite breeding lineCUZS1313 to create test-hybrids for the Turkish market. These 220test-hybrids were used in yield trials in Turkey.

Yield Experiments

Two different yield experiments have been carried out to detect yieldrelated QTLs, one experiment in the Netherlands (NLD) and one experimentin Turkey (TUR).

Yield-Experiment—the Netherlands (NLD). Detecting QTL2.1

The aim of the yield experiments was to measure yield for long-cucumberduring the summer-autumn period. The experiment consists of the 220test-hybrids and 30 repeats of the genetic control. The 250 plots havebeen sown in June 2009 by hand in trays with rockwool plugs. The trayswere kept during 4 days at a temperature of at least 24° C. 4 days aftersowing, the plugs with germinated seeds were transplanted on rockwoolblocks. During approximately 3 weeks the rockwool pots were kept in aspecific compartment of the greenhouse, the plant-raising area. In thisarea the plants will grow until they are ready for planting in thegreenhouse. The plants of roughly 30 cm height were transported to thegrower about 4 weeks after sowing. At the grower 8 plants per plot weremaintained. In total the experiment exists of 250 plots*8 plants. Theexact number of plants per plot was recorded. The plants were grown inthe traditional Dutch way. That means that the plants were grownvertically, supported by a wire till roughly 220 cm height. At thisheight the top of the plant is removed and the plant will continuegrowing on the laterals. About 3 weeks after plantation the first fruitscan be harvested. The harvest period started in August and continueduntil the end of October. Plants were harvested between 3 to 7 times perweek. The yield was measured in two different ways. The total number offruits per plot were counted and divided by the number of plants of thatplot per harvest day. The harvests of all days were cumulated. Thisresults in the cumulative yield expressed in average number of fruitsper plant (FrPP). The second measurement was to take the cumulativefruit weight per plot and divide that by the number of plants to obtainthe average fruit yield in gram per plant (GrPP).

The yield data was used to detect QTLs. On chromosome 2, a QTLpositively affecting yield was identified located between about 5 Mb and11 Mb of chromosome 2.

Table 1 shows the performance of the test-hybrids with an introgressionfrom the wild relative of cucumber on chromosome 2 (donor) versus thegenetic control lacking the introgression on chromosome 2. The yieldincrease was on average 5% when expressed in GrPP and 18% when expressedin FrPP.

TABLE 1 Yield of test-hybrids containing an introgression on chromosome2 from the wild relative of cucumber (donor) versus a genetic controllacking the introgression on chromosome 2. Yield data is based on atrial in the Netherlands (NLD). The yield is expressed in average gramper plant and in average fruits per plant (GrPP and FrPP, respectively).Yield in average gram Yield in average fruits per plant (GrPP) per plant(FrPP) Genetic control hybrid (lacking QTL2.1) 17957 40.8 Test-hybridswith QTL2.1 introgression 18857 48.0 from donor Yield increase due toQTL2.1 5% 18% introgression from donor

Yield Experiment in Turkey (TUR). Detecting QTL6.1

The aim of the yield experiments was to measure yield for long-cucumberduring the autumn-winter period in Turkey. The average minimumtemperature in December, January and February was about 6.5° C. Suchtemperatures give considerable cold-stress to the cucumber plants. Onlyadapted genotypes will continue producing cucumber fruits under coldstress. Greenhouses were equipped with heaters to prevent frost in thegreenhouse. A minimum temperature of 8° C. in the greenhouse was aimedfor. The maximum temperature in the greenhouse depends on outsidetemperatures and sunlight and can go up to 30° C. in this period.

The experiment consists of the 220 test-hybrids plus 11 repetitions ofthe control variety Kybele F1 (Vilmorin). The 231 plots were sown inOctober 2009 by hand in trays with peat plugs. The trays were kept in acompartment with a minimum temperature of 20° C. Four weeks after sowingthe plants were transplanted in the greenhouse. In the greenhouse 8plants per plot were maintained. In total the experiment consisted of231 plots*8 plants. The exact number of plants per plot was recorded.The plants were grown in the common way for short cucumber in Turkey.That means that the plants were grown vertically, supported by a wiretill roughly 220 cm height. At this height the plants were guided backover the wire to the ground. When the top of the plant reached about 1meter above the soil the top of the plants were removed. Laterals wereremoved on the main stem until the wire. The first harvest of fruits wason December 9th. Fruits were harvested once or twice a week until March30^(th), 2010. The yield was measured in the two different ways. Thetotal number of fruits per plot were counted and divided by the numberof plants of that plot per harvest day. The harvests of all days arecumulated. This results in the cumulative yield expressed in averagenumber of fruits per plant (FrPP). The second measurement was to takethe cumulative weight per plot and divide that by the number of plantsto obtain the average yield in gram per plant (GrPP).

The yield data was used to detect QTLs. One yield related QTL wasdetected on chromosome 6 between about 25 Mb and 29 Mb of thechromosome. As the QTL was found under cold-stress, it can also beconsidered as a cold-tolerance QTL.

Table 2 shows the performance of the test-hybrids with an introgressionfrom the wild relative of cucumber (donor) on chromosome 6 versus thetest-hybrids lacking the introgression on chromosome 6. Test-hybridswith the yield related QTL on chromosome 6 had a 33% higher yieldexpressed in GrPP compared to material lacking the introgression, and a34% higher yield when expressed in FrPP. Compared to winter-varietyKybele used as control the yield increase was 26% (in GrPP) or 25% inFrPP.

TABLE 2 Yield of test-hybrids containing an introgression on chromosome6 (chr6) from the donor versus test-hybrids lacking the introgression onchromosome 6. Yield data is based on a trial in Turkey. The yield isexpressed in gram per plant and in fruits per plant (GrPP and FrPP,respectively). The production of winter variety Kybele F1 (Vilmorin) ismentioned as a reference. Yield in average gram Yield in average fruitsper plant (GrPP) per plant (FrPP) Kybele F1 (control) 4692 34.9Test-hybrids lacking QTL6.1 4429 32.6 introgression Test-hybridscomprising QTL6.1 5889 43.7 introgression from donor Yield increase dueto QTL6.1 33% 34% introgression from donor compared to test (26%) (25%)hybrids lacking QTL6.1 (in brackets: compared to variety Kybele F1)

Validation of Yield Increase Due to Introgression Comprising QTL2.1

Based on the results of the QTL-detection trials, one particularBC2S2-line, containing the introgression on chromosome 2 (QTL2.1), hasbeen selected. This line was crossed with breeding line HMRKC togenerate a BC3 line (backcross 3). The BC3 was self-pollinated for twogeneration to create a BC3S2-line only containing the introgression onchromosome 2 from the donor. This line was crossed to breeding lineCUZL0176 to create a new testcross (PRE.N1.CH2.1001). For comparisonbreeding line HMRKC was crossed with CUZL0176 to create a geneticcontrol, seeds of which were deposited by Nunhems B.V. under accessionnumber NCIMB42345.

The two materials (PRE.N1.CH2.1001 and NCIMB42345) were tested in ayield trial in summer/autumn 2013. In a similar way as described above(yield experiment—NLD), the materials were trialed in 4 repetitions of 8plants.

Table 3 shows that the yield increase of the line containing the yieldQTL on chromosome 2 (QTL2.1) is 4.3% when expressed in GrPP and 5.0%when expressed in FrPP, confirming the findings in the earliergenerations that the yield related QTL on chromosome 2 increases thecucumber yield.

TABLE 3 Yield measurements in 2013 for 1 trial of 4 replicates and 8plants per replication of genetic control NCIMB42345, a cross betweenHMRKC and CUZL0176, and of PRE.N1.CH2.1001, a cross between CUZL0176 anda BC3S2 material based on backcross parent HMRKC containing anintrogression of the donor on chromosome 2. Yield is expressed incumulative fruits harvested per plant (FrPP) and cumulative grams perplant (GrPP) as described above. Yield in average gram Yield in averagefruits per plant (GrPP) per plant (FrPP) Genetic Control (NCIMB42345)14336 34.3 PRE.N1.CH2.1001, comprising QTL2.1 14960 36.0 Yield increasedue to QTL2.1 4.3% 5.0% introgression from donor It is noted thataverage fruit length was not affected, i.e. not different between thegenetic control and PRE.N1.CH2.1001.

Validation of Yield Increase Due to Introgression of QTL6.1

Based on the results of the QTL-detection trials, one particularBC2S2-line, containing the introgression on chromosome 6 (QTL6.1), wasselected. This line was crossed with breeding line HMRKC to generate abackcross 3 line (BC3). The BC3 line was self-pollinated for twogeneration to create a BC3S2-line only containing the introgression onchromosome 6 (QTL6.1) from the donor. This cleaned-up line was crossedwith 2 parents for the Spanish winter market: breeding line CUZL0224 andCUZL0876, and it was crossed with two parents for the Turkish wintermarket: breeding line CUZS1329 and CUZS0683.

Thus, the following materials have been developed:

Turkey: PRE.N1.CH6.9001, comprising QTL6.1, based on a cross withCUZS1329, and PRE.N1.CH6.11001, comprising QTL6.1, based on a cross withCUZS0683. The following two genetic controls, lacking QTL6.1, were used:PRE.N1.9GC and PRE.N1.11GC, respectively.Spain: PRE.N1.CH6.2001 comprising QTL6.1, based on a cross withCUZL0224; and PRE.N1.CH6.7001 comprising QTL6.1, based on a cross withCUZL0876. As genetic control the materials PRE.N1.2GC and PRE.N1.7GCwere used.

In Turkey the material has been tested in the winter of 2013/2014. 8replicates of the two test-hybrids and the 2 genetic controls weretested. Results are in Table 4 below.

In Spain the material has been tested in the winter of 2014/2015. 8replicates of the two test-hybrids and the 2 genetic controls have beentested. Results are in Table 5 below.

TABLE 4 Yield measurements in 2013/14 in Turkey Yield in average gramYield in average fruits per plant (GrPP) per plant (FrPP) PRE.N1.9GC(genetic control, lacking 2209  9.4 QTL6.1) PRE.N1.CH6.9001, comprisingQTL6.1 2329 10.8 Increase due to QTL6.1 5.4% 15% PRE.N1.11GC (geneticcontrol, lacking 2012 10.8 QTL6.1) PRE.N1.CH6.11001, comprising QTL6.12139 12.2 Increase due to QTL6.1 6.3% 13%

TABLE 5 Yield measurements in 2013/14 in Spain Yield in average gramYield in average fruits per plant (GrPP) per plant (FrPP) PRE.N1.2GC(Genetic control lacking 19.6 8.0 QTL6.1) PRE.N1.CH6.2001 comprisingQTL6.1 20.6 8.4 Increase due to QTL6.1 5.1% 5.0% PRE.N1.7GC (Geneticcontrol lacking 20.7 8.5 QTL6.1) PRE.N1.CH6.7001 comprising QTL6.1 21.78.6 Increase due to QTL6.1 4.8% 1.2%

Combining QTL2.1 and QTL6.1 in Long Cucumber

A test-hybrid was made comprising both QTL2.1 and QTL6.1 and was trialedin a greenhouse in Canada in the spring of 2015 in two replicates of 8plants each. As a comparison commercial varieties Verdon F1 (RZ 24-150,Rijk Zwaan) and Sepire F1 (NUN43003, Nunhems) were used. The averagenumber of FrPP was determined.

TABLE 6 Yield in average fruits per plant (FrPP) Verdon F1 37.5 SepireF1 35.8 Test-hybrid comprising QTL2.1 and 40.7 QTL6.1 Increase intest-hybrid compared to 8.5% Verdon F1 and Sepire F1 13.6%

A deposit of 2500 seeds of a long cucumber BC1S3 line, comprising bothQTL2.1 and QTL6.1 in homozygous form was made by Nunhems B.V. underAccession number NCIMB42545 on 18 Feb. 2016.

Example 2

Single Nucleotide Polymorphism markers (SNPs) were identified spanningthe introgression fragments on chromosome 2 (comprising QTL2.1) and onchromosome 6 (comprising QTL6.1) and their position on the physical C.sativus map was determined.

TABLE 7 SNP markers for QTL2.1 introgression fragment Genotype ofGenotype introgression of recurrent Genotype of fragment parent hybridPhysical position (homozygous lacking (heterozygous SNP of SNP (base forintrogression for Genomic sequence marker number) QTL2.1) (HMRKC)QTL2.1) comprising SNP SNP_01 5,502,468 CC TT CT TTGTATAAGAAAGAAGATCATACAAATTATGAACATGG TTGATAAATTTTGGATGTT GTACCTAAAACATGGAA[C/T]AGAATCTCCTATTTAA TCCATCACAACAACAATAA TATAAATAGTAAATAAACAAATTAAATAATTTTWCGAA AG (SEQ ID NO: 1) SNP_02 5,716,997 GG AA GATGCTTCTTCTTGACCATCT TTACCCTCTTTCTTGACCA TGCTGTTGTACAGGTCCATCTGTAAATGGAGACAAT[A /G]GCAAGAAAAAAGTACC GACCAATTAGTCATGTACTAGGGTTTTCCAGCTCAAAA TACATTTGGGTCCTGAAGA TC (SEQ ID NO: 2) SNP_036,025,329 GG AA GA ATTTCCTTCTTAACTTCTA AAAAAGAGGTAGTAACTTCAGATAACTTTTGGGCATGA TGAGAACTGTTTAAAGC[A /G]GTTAGTGTTGGTAATAACGAAGATTGCCTCAATAA TTCTTTCCATTGAGGATTC CCATGGGATTTTGTTGATG AT(SEQ ID NO: 3) SNP_04 6,108,038 TT CC TC CAGCACTTCTTCTTTCCAATGTTTCGATATCTACAAAC TTTTTTGGGATGTTTTTGT GGGCTTGTTTTCTTTTA[C/T]GTTTTCTCAATTGGAG TTGTTGCTTTCAATTTTTT TTTACAAAAAGGAAATCCAGAAATGGCCCCCATATTTA CA (SEQ ID NO: 4) SNP_05 6,143,786 TT CC TCGAAATAAGGCAAAAGAATA ATTCCTCCGAATGTCAATG TGGATCAAGACTAAGAGTAAGAAAATTAAATTAAAC[C /T]ATTACCATGATTCCAG CTGCCACTTACTGCTGTCAGCCGTTGCCCTCATCCTTT ACTCTGTGGTCCACACCTT CA (SEQ ID NO: 5) SNP_066,309,854 CC TT CT CAATTTAACGAATATTTTA TTCAGTCACAATATCATCTTGATTTCGAACATAGCAAA ATGAATCAAAATATTTA[C /T]GACCATAGCAAAATCTCAATGTCTATTAGTGATAG ACACTGAGACACCAATAGA CACTGATAAATATCTAAAA CT(SEQ ID NO: 6) SNP_07 6,692,001 CC TT CT ATATTTTACTTTAGYATTAAGWCGTTATAACAATTAAG CTAAAAGAAGGTAATGCTA ACGATACTAATTACTTA[C/T]AGCTTGAGACTCACAC ACAGAGACTAAATTAATCT AGGGGAGAGTGAAATGATTTAACTTGTATGTAGATGAA GG (SEQ ID NO: 7) SNP_08 6,923,609 AA GG AGGTTGAGGACTTGGTCTATG TTTGTCAAGAATAACACAT TTGATTTCTTCTTTTGATCAGTTTCTAATTGGGATG[A /G]AAATACCACACTACAC TCTTTGATGCTCACTTTTAGGTCTTGTGGAAGAAGAAT TGGACTCTTTTGGTGGAAG CT (SEQ ID NO: 8) SNP_097,100,287 TT GG TG TTAATTTCTTCTTCTTTTA GWATTCTTGGAAGTTTTTTAAGTATTCCATTCCTTTTG CTAAATCAGTTATTTTT[G /T]TACACAAAAAAGAATAACGGCAGCAGACTAGAATC CACATTGATAACATAGATT CCATATTAAAAATTATGAT GA(SEQ ID NO: 9) SNP_10 7,509,399 TT GG TG AAATGTTGCATAAGAGGAGTACACTTTAATTAAAATTG GAACAGTCAATTTTTATGA TTTTCAGTTTCAGATAT[G/T]GAGAACATTTGAATGT AAATGGGGTGACTCATCTA TTGCGCAACCCAGACAGCATCCATATGCTCCTTTCACA AC (SEQ ID NO: 10) SNP_11 7,647,391 GG AA AGTAGAAGATACGCACCCCAA CTGGCAACCTAAGGGAACA GCCAACAGAAGAATAATAAACAAATGCATGAACCTA[A /G]GAGAATTTGAAGTGCA TCACAGGAAATTAAGAAAAAAGCAAGCATAAAGCATAA CTAGAATAGCATACCCCGC AA (SEQ ID NO: 11) SNP_127,741,866 GG TT GT GTAGTGTAAAAGAAAAAAA TATGAATGATTGTAGACATGGCCCACGTTAATGAACTT TCAGCTATTTTTAGTTT[G /T]ACTTTTTGAACTCTACTTTGAGTGCACTTCTGATC ATTAACTAGAAATATTTTG GTAGGTGCAAGAGCTGACT TG(SEQ ID NO: 12) SNP_13 7,897,510 CC AA CA CATAACTCTTTATTTTGGGTGATCTATTGTGATAGACT TGATGTATAACTTATAAAG TTTTCATAGTTCAGTTG[A/C]GTGGTTTATTGCGATA GACTTGCTGAAGCATCCAA TGTGTGAAAGTGAAGGTGTGARTTACCTTCTATKAGAK AG (SEQ ID NO: 13) SNP_14 8,096,008 AA GG AGTTATTACAATGGTCAAAGT GGCATTTGTTAATTCATTT AAGAGGAGGAGAAAAAACAGATCTTCAGTCAAAAAG[A /G]GAAGTTGAATAGTGAG GCCTACCGTGTGAAAAGGCACGTTATCCTTTCCCATAA ATTGAAAAAGCTCTACATT TT (SEQ ID NO: 14) SNP_158,477,379 CC TT CT CTTTGAGCCTCTAATYGAG GTTAAACAAATTTCAATCTTTCATAATTGACTTCCGAA GATAATCAAGAGCAATC[C /T]TTGATAGCACCAAAAATGTGTTTTCTATCTCTACG TAATTCGAGCTCCTTCCTT CATTTTACTTTCTTATTTG GT(SEQ ID NO: 15) SNP_16 8,960,281 AA CC AC ATCTTGTCAGTCTCCGGATTTCATCTAGAATGGTTGTT GAAGGCAGTCTCAGAATTA TTAAGAGGGCCAAAGGA[A/C]AAGTTTTTTAAAAGCT GGATGAAGTGGATAGAGGT AGATTGAAAGTTTAAAATTTTAAAACAAAGATTGGCTG GG (SEQ ID NO: 16) SNP_17 9,014,202 TT CC TCTGAAACTGAGACGATATGG AGATTTCAGATTTGACGCT TCCCAATGAATCTAGTTGGCTTCCTTGGGATTACCA[C /T]TTCACATTGTTTTTTT TTTGTGTGTGTGTGGTGGGGGGACTTTGGTTTTCTTTT CCCTTCTAATTTTTTTGCT AA (SEQ ID NO: 17) SNP_189,138,840 GG AA GA GTGTTGGAGTAACACGAAC TGCAGAATACAAGAACAGATTATTAGGAAAAAAACCTC ATAAATCATATTCTTAC[A /G]AATAAGTAATTTGGGATATAGTAAGAAAAAGAAAA AAAAAAGATAGAATTATAT GTATATAGTACCCATATAA TC(SEQ ID NO: 18) SNP_19 9,296,199 AA GG AG CCCAGTTCAGATGGAAGTTGCCCATTAAACTTATTGTT GTTCAGAATTAGATATTCC AACCTGATACAATCGCC[A/G]ATCTCTTTCGGTATAA TTCCGGTGAGTTCATTGAA GGAAACATTGAGATAAGTCAGGTGGATCAACTTACCAA TG (SEQ ID NO: 19) SNP_20 9,490,021 GG AA GAATTGGTTGCCACTGACTTG AATGTTGGAACAAATTTTC AGTCATGAGGAGAATCAGATTATCATTTGGAAATGT[A /G]TATATATGCAATAATT AAGTGAAAATTTTCTATTCGTGCTCTTTTAACGAGGAA CAAATCTTTTTTCCATTGG TA (SEQ ID NO: 20) SNP_219,697,081 GG AA GA CTAAATACCTTATCTTCAT CTACTAGTATATATTTTATCCTGTTTCTCATACTGAGT TGCATATTTGAGAAGAG[A /G]GACTATATGTGCTTGTTTCTGTGTGTTTATTTATA ATTCTCATCTTTTGGTTGT CAATATGAAGAATGCTGAT TT(SEQ ID NO: 21) SNP_22 10,119,285 GG TT GT TTATAAGATCAATTACTCAAARTTTCAAAAAGCCATCT AATCAATGTTAGCCTAAAC GTTTTAAGTCAGATAAT[G/T]AACTTAATATCATGAT ATGATATATATGAAAGTGA AATCTATTTAGAATCTCTATAAGACCCACTGTATCCAT CA (SEQ ID NO: 22) SNP_23 10,337,700 TT GG TGGGAATTAAAAGTGTATGAA GAAGAGAGACCTCCAATTG AGTAGAGCAGTTAATGAGAGGCCTGGCTTTGTGTTT[G /T]CCATCAATTAACTTGG AAAGAAACAATGTGATATCAGTTGGAAAATGATCAGTT TGATCCACCAACCATCTAT AW (SEQ ID NO: 23) SNP_2410,773,430 GG TT GT TAGTTCAAATTACTTCATG TTTAGATTAATGTTTAAAGAAATGGGGAGTCTGCCATT ACCAGTAATCACTCTAT[G /T]ATTGCAAGTTTAGAATCCAATGACAAAGAAATGAA AAAATATTTGTAAGAACAG TTGTGGAAAATTACAACTT TT(SEQ ID NO: 24) SNP_25 10,853,468 GG AA GA GATTTGGAGGAGATTTTCCAGCAACATTCCAAGTAGCT ACAAAGATTCTATTCATTT AAACAGAAAGAAGAGAG[A/G]CAAAGAAGGAATTAAA GACATAGTCCAAAGAATTC ATTGCCTGGAAACAACAAAATAGAGCATACATACCGGT AA (SEQ ID NO: 25) SNP_26 10,882,440 CC AA CACGTGTACTTTCTTTTCAGT TTAACCTTAAAAGTAATAT TTAACTAGTAGTTTGGATTTAAAGTTCGTGCTTTTT[A /C]ATTTCAACAATTAGTC AACTGTAATAAGATATCGTTGCAACTTTATTCTATTCT ATCATGTCACTTGCTGTGA TC (SEQ ID NO: 26)

TABLE 8 SNP markers for QTL6.1 introgression fragment Genotype ofGenotype introgression of recurrent Genotype of fragment parent hybridPhysical position (homozygous lacking (heterozygous SNP of SNP (base forintrogression for Genomic sequence marker number) QTL6.1) (HMRKC)QTL6.1) comprising SNP SNP_27 25,519,964 GG AA GA TGATKTTGATCTCTTCCCTTAATCACGTAATAGGCAAC TTTTGCTTTTTCTCTTTTT GTGTGTGCTTTCTGTTC[A/G]ACTTAAAATATATATG AGTGTGACTAATTATACTT TTAACTACCTAATATATATTTATTTCCATCCGATTAAG TT (SEQ ID NO: 27) SNP_28 25,702,190 TT CC TCAAACGAAATGTTTAAAGAA TGAAATATTCCCAATTGGT AAGGAGTAATCAATCTACATAATAATGGGTTTGAAC[C /T]AAAAAAATGAAATTTG TAGCTACAAAAAAATTGAAGCTGAGAGAGTAAATTCAA TGGATGATCAAACAATTTG GG (SEQ ID NO: 28) SNP_2925,723,504 CC AA CA TTGTCAGTTAAGAAATCTC CAGTACAAGAATTTACAACAATACTTGAACAGCCGCGA TAGATGATGTATGAAAA[A /C]GGATTAAAGATCGAAACTAAAGGAAGGTGGTTCCG ACGATCATGAGCCCTTGAA TACAGAAGTCGGAGATAAT GG(SEQ ID NO: 29) SNP_30 25,898,678 TT CC TC AAWTTTTGTTARATTTTAGCTCTTAAACTTTTTGAACT TAGTCTCTATACTTTCAAA TTTGTAATAATTTTAAC[C/T]CACCATAATAAACCAT ATCAGAATTAAGTGTTATT TTTTATTGCCTAACAACATTTTCCATAGTTTATAAACA AA (SEQ ID NO: 30) SNP_31 26,116,120 TT CC TCCTGAAACCTCTTAGCCAAC TTTCTTTGGCAGGCCTTTA AAAACCGGGATCCTGCTTGTTTGTCTTACAGTTCAG[C /T]GCTTCTATATCCTAAG GTAATTGATATTTTCAAATCAAGCGGCTTAGTTTGGTT CACAGAGCTGTTCACCGTC CT (SEQ ID NO: 31) SNP_3226,300,206 CC TT CT AAAACCAGTGAGAAATTGA GAAGCTTGTTGAGTTTACTAACCGGTGTTTTAATCTCT TGACAGGTGAATGATTA[C /T]GTGCAGTCGCACATACAAATAAATGAGTATCGGGA TCGTGTTATTCTGGTGAGT TACTGAATTCTGGGATTCG AC(SEQ ID NO: 32) SNP_33 26,501,889 GG AA GA TATAWATTTGWATSTTCAATTTWAAATTAAAGAATAAG GTATTCCAATAAAGAACCA ATAGGTCTAATAAGCTC[A/G]AGAATCAAAAGTAGGA AGACTAGTCAACAAGAGGG ACAACTAACTCAACTCCATAAAAAGTGTTCAGTTATAC AA (SEQ ID NO: 33) SNP_34 26,799,539 TT CC TCTTCATGGTTTCAACCACCG TTTCTCAAACAGACATCAT AACCCATTCATGTTCAAACACCGGCAACTACACCAC[C /T]AACAGCGTTTACAAGC AAAATCTCGACAACCTCCTTTCCTCCATCGCCTCCAAC ACCGAAATTGATTACGGCT TT (SEQ ID NO: 34) SNP_3526,903,056 GG AA GA AGATATGGTATAAAAGTGT YGCTACAACTCACTGTTTTCAAAACTATATATTAAAAA TTGTAGACAGAGAAAAT[A /G]GAGAAAAGTAAAAACAGCTCTTACATTACCAATCA ATTGATCCAAAAAATTTAA CTTASTAGGCTTGTTCTTY TT(SEQ ID NO: 35) SNP_36 27,146,553 AA CC AC TGTGGGTAACGGAAGAAGATGAATGCTTGGTTGGTATT ATCACCTTCACGTCGATGT TGAAGGTTTTCCACGAG[A/C]GTTTGAAATCAATGTG TTGAAAGAACACATCAGCA AGAGCTTCGCCCTGATCTTAAGCTGAAGCTATATAATG AM (SEQ ID NO: 36) SNP_37 27,505,742 AA GG AGTGCAAACATTTAGAACCCT GGCTGTTTGTGTATCTCAA GAAATGAGGAATTTGTAAATGCAGTAATCTTACCAT[A /G]TGAGAAAGTGATAGAG CGAGATAAATCAACTTGAGCGTAACTCAAATGTTAAGA TATTATAATCTCAGTCAAA AG (SEQ ID NO: 37) SNP_3827,702,768 AA GG AG AATAATTTGGTTCCCAATT TCACTCCGCATTTAAACTTTGCTTCTTATGCCTACAAA TTCTTCCCCATCGTCTG[A /G]GTTTTACTTTTTTAACCAAACTCCATCTATTTTTT CATTCACTTCATTGGTGGA TTGAAACGCTTCTACGTTT AA(SEQ ID NO: 38) SNP_39 28,114,353 AA CC AC TATTCAAACTAAAACTCCCATTTTTCGATTCCTTTTAA TATTAGTTTTCATATTTCT ATGGTCTCTGTTTCTTT[A/C]TAAACCTCACACACTC TAGAATGTTCACTACTTTA TTAATATGGTTCTTGGGAATTATGGATTCAATAAACTA TT (SEQ ID NO: 39) SNP_40 28,300,913 TT CC TCAATGCAAGAAAAGTAGATC CAAGAAGTGCGCTTTCAAG GTTGATAGATTCTATTTATGTATGAAAAGATCATCT[C /T]ATCTGCAATTATAATT TACAATTTGGTATGCATATGCAAGCATGAAATAACATT CATCAATACATAAAAGATA TG (SEQ ID NO: 40)

1-13. (canceled)
 14. A cultivated Cucumis sativus var. sativus plant, orplant cell, tissue, plant part or seed thereof, comprising anintrogression fragment on chromosome 6 in homozygous or heterozygousform, wherein said introgression fragment is the fragment as found onchromosome 6 in seeds of which a representative sample has beendeposited under accession number NCIMB 42545, wherein said introgressionfragment comprises a Quantitative Trait Locus referred to as QTL6.1,which confers an increase in cucumber fruit yield, and wherein saidintrogression fragment on chromosome 6 comprises at least one of thefollowing markers: a) the GG or GA genotype for the Single NucleotidePolymorphism marker SNP_27 in SEQ ID NO: 27; b) the TT or TC genotypefor the Single Nucleotide Polymorphism marker SNP_28 in SEQ ID NO: 28;c) the CC or CA genotype for the Single Nucleotide Polymorphism markerSNP_29 in SEQ ID NO: 29; d) the TT or TC genotype for the SingleNucleotide Polymorphism marker SNP_30 in SEQ ID NO: 30; e) the TT or TCgenotype for the Single Nucleotide Polymorphism marker SNP_31 in SEQ IDNO: 31; f) the CC or CT genotype for the Single Nucleotide Polymorphismmarker SNP_32 in SEQ ID NO: 32; g) the GG or GA genotype for the SingleNucleotide Polymorphism marker SNP_33 in SEQ ID NO: 33; h) the TT or TCgenotype for the Single Nucleotide Polymorphism marker SNP_34 in SEQ IDNO: 34; i) the GG or GA genotype for the Single Nucleotide Polymorphismmarker SNP_35 in SEQ ID NO: 35; j) the AA or AC genotype for the SingleNucleotide Polymorphism marker SNP_36 in SEQ ID NO: 36; k) the AA or AGgenotype for the Single Nucleotide Polymorphism marker SNP_37 in SEQ IDNO: 37; l) the AA or AG genotype for the Single Nucleotide Polymorphismmarker SNP_38 in SEQ ID NO: 38; m) the AA or AC genotype for the SingleNucleotide Polymorphism marker SNP_39 in SEQ ID NO: 39; or n) the TT orTC genotype for the Single Nucleotide Polymorphism marker SNP_40 in SEQID NO:
 40. 15. The plant according to claim 14, wherein said increase incucumber fruit yield is phenotypically expressed as a significantlyhigher average number of fruits per plant (FrPP) of the plant linecomprising the introgression fragment compared to the genetic controlline lacking the introgression fragment when grown under the sameenvironment and/or a significantly higher average fruit weight per plant(GrPP) of the plant line comprising the introgression fragment comparedto the genetic control line lacking the introgression fragment whengrown under the same environment.
 16. The plant according to claim 14,wherein said Quantitative Trait Locus QTL6.1 is located in betweenSNP_27 at nucleotide 75 of SEQ ID NO: 27 and SNP_40 at nucleotide 75 ofSEQ ID NO:
 40. 17. The plant according to claim 14, wherein saidintrogression fragment is in heterozygous form.
 18. The plant accordingto claim 14, wherein said introgression fragment is in homozygous form.19. The plant according to claim 14, wherein the plant is of one of thefollowing cucumber types: slicing cucumber, long cucumber, or Europeangreenhouse cucumber.
 20. The plant according to claim 14, wherein theplant is a single cross F1 hybrid or an inbred line.
 21. The plantaccording to claim 14, wherein the plant produces seedless fruitswithout pollination.
 22. Seeds from which a plant according to claim 14can be grown.
 23. The plant according to claim 14, wherein saidintrogression fragment on chromosome 6 comprises at least two of themarkers.
 24. The plant according to claim 14, wherein said introgressionfragment on chromosome 6 comprises at least three of the markers. 25.The plant according to claim 14, wherein said introgression fragment onchromosome 6 comprises at least four of the markers.
 26. A cultivatedCucumis sativus var. sativus plant, or plant cell, tissue, plant part orseed thereof, comprising an introgression fragment on chromosome 6 inhomozygous or heterozygous form, wherein said introgression fragment isa smaller fragment derived from the fragment as found on chromosome 6 inseeds of which a representative sample has been deposited underaccession number NCIMB 42545, wherein said smaller fragment comprises aQuantitative Trait Locus referred to as QTL6.1, which confers anincrease in cucumber fruit yield and comprises at least one of thefollowing markers: SNP_27 to SNP_33, or SNP_33 to SNP_40, or SNP_29 toSNP_38, wherein SNP_27 comprises a G at nucleotide 75 of SEQ ID NO: 27;SNP_28 comprises a T at nucleotide 75 of SEQ ID NO: 28; SNP_29 comprisesa C at nucleotide 75 of SEQ ID NO: 29; SNP_30 comprises a T atnucleotide 75 of SEQ ID NO: 30; SNP_31 comprises a T at nucleotide 75 ofSEQ ID NO: 31; SNP_32 comprises a C at nucleotide 75 of SEQ ID NO: 32;SNP_33 comprises a G at nucleotide 75 of SEQ ID NO: 33; SNP_34 comprisesa T at nucleotide 75 of SEQ ID NO: 34; SNP_35 comprises a G atnucleotide 75 of SEQ ID NO: 35; SNP_36 comprises a A at nucleotide 75 ofSEQ ID NO: 36; SNP_37 comprises a A at nucleotide 75 of SEQ ID NO: 37;SNP_38 comprises a A at nucleotide 75 of SEQ ID NO: 38; SNP_39 comprisesa A at nucleotide 75 of SEQ ID NO: 39; and SNP_40 comprises a T atnucleotide 75 of SEQ ID NO:
 40. 27. The plant according to claim 26,wherein the smaller fragment comprises markers SNP_27 to SNP_33.
 28. Theplant according to claim 26, wherein the smaller fragment comprisesmarkers SNP_33 to SNP_40.
 29. The plant according to claim 26, whereinthe smaller fragment comprises markers SNP_29 to SNP_38.
 30. The plantaccording to claim 26, wherein the introgression fragment is inheterozygous form.
 31. The plant according to claim 26, wherein theintrogression fragment is in homozygous form.
 32. The plant according toclaim 26, wherein the plant is one of the following cucumber types:slicing cucumber, long cucumber, or European greenhouse cucumber. 33.The plant according to claim 26, wherein the plant is a single cross F1hybrid or an inbred line.